Muscle Pain: Possible Causes

The causes of muscle pain can vary. Also called myalgia, aching muscles can be caused by an injury, a symptom of a disease or infection, or a side effect of a medication.

Muscle pain can also feel different—aching, cramping, stabbing, or burning—depending on what is causing it.

This article explores several possible causes of muscle pain and what you can do about each one. It also highlights which symptoms may warrant a call to your healthcare provider.

Causes of Localized Muscle Pain

Localized muscle pain refers to pain that is centered around one muscle or a group of muscles.

Muscle Strain

Injuries are a common cause of muscle pain. A muscle can become injured as a result of strenuous exercise or sudden movement. When a muscle is overstretched, it can lead to a muscle strain (a.k.a. a pulled muscle).

By definition, a muscle strain is an injury to a muscle or a tendon (the fibrous tissue that connects muscles to bones). Muscle strains can sometimes be minor, while severe strains can cause these tissues to tear.

Muscle pain from a strain usually feels like a sudden sharp or tearing sensation. The pain may also be accompanied by swelling or bruising.

Initial treatment with the RICE protocol is usually very effective. RICE stands for Rest, Ice, Compression, and Elevation. Nonsteroidal anti-inflammatory drugs (NSAIDs) like Aleve (naproxen) or Advil (ibuprofen) can treat swelling and pain caused by muscle strains. Physical therapy can aid long-term recovery.

Muscle Contusion

Muscle pain can also be caused by a muscle contusion. Also known as a muscle bruise, this injury can occur as a result of a direct blow to the muscle, causing tiny blood vessels called capillaries to bleed and surrounding tissues to swell.

In addition to muscle pain, the overlying skin may develop bruising (known as a skin contusion). In some cases, a hematoma (a contained pool of blood) may form in or around the injured muscle.

Most contusions are mild and respond well to the RICE protocol. Muscle relaxants like Flexeril (cyclobenzaprine) and Zanaflex (tizanidine) may help ease the pain of an acute muscle injury. If symptoms persist, talk to your healthcare provider to prevent permanent damage to the soft tissues.

Myofascial Pain Syndrome

Some people experience muscle pain as a symptom of a chronic condition.

Myofascial pain syndrome (MPS) is a pain disorder caused by trigger points within a muscle. Trigger points are tight bands of muscle and/or fascia (tissues surrounding muscles) that feel like tiny knots beneath the skin.

Trigger points may be tender to the touch. They can also cause shooting pains to other parts of the body (known as referred pain).

A common trigger point is in the upper trapezius muscles situated at the back of the neck above each shoulder. These trigger points can cause a deep aching or burning sensation in the back or side of the head.

Treatment options may include medications, such as NSAIDs for swelling and pain, tricyclic antidepressants such as Elavil (amitriptyline), or antidepressants like Cymbalta (duloxetine) may be used for pain relief.

Other treatments may include:

• Physical therapy
• Trigger-point release massage: a daily practice that involves the compression of trigger points using your fingers, a foam roller, or a massage ball
• Spray-and-stretch therapy: spraying a vaporized coolant over muscles while massaging the skin in the direction of the referred pain
• Local injection of an anesthetic with or without a steroid

Compartment Syndrome

Some causes of muscle pain are serious.

Compartment syndrome is an uncommon condition that occurs when pressure builds within a group of muscles. The pressure can arise from internal bleeding or the swelling of tissues.

Compartment syndrome can reduce blood flow to regional muscles and nerves, depriving them of oxygen and nourishment. If the pressure is severe, nerve, skin, and muscle tissues can start to die.

Symptoms of compartment syndrome include pain, numbness, pins-and-needles sensations, and increasing weakness in the affected area. The symptoms can range from mild to severe.

Physical therapy, orthotics (inserts for shoes), and anti-inflammatory medicines may be some initial treatment options. Sometimes modifying activities, such as doing low-impact cross-training, changing the training surface, or changing running gait can relieve symptoms. Severe compartment syndrome may require a fasciotomy in which the fascia covering a muscle or group of muscles is cut open to relieve pressure and restore blood flow.

Pyomyositis

Muscle pain can also be a sign of an infection. Some of these infections can be very serious.

Pyomyositis is a rare infection of muscle tissues usually caused by a bacteria called Staphylococcus aureus.

Pymositis can cause cramping and pain within a single muscle group, most commonly the thigh, calf, or buttock muscles. As the infection progresses, a fever can develop. There may even be an abscess (a collection of pus) visibly emerging from the muscles beneath the skin.

Early pyomyositis may be treated with antibiotics, but if an abscess has formed, draining the abscess through needle biopsy or open surgical drainage is required. If not treated, the infection can spread to other organs, like the heart, lungs, and brain.

Causes of Systemic Muscle Pain

Another kind of muscle pain is called systemic myalgia. These muscle aches are usually related to an infection, medication side effect, or underlying disease.

Infections

Certain types of infections, especially viral, may cause muscle pain. Perhaps the most common infectious cause is the flu, which can cause generalized aches and pains. COVID-19 is also known to cause myalgia.

Other infections that can cause muscle pain include:

Viral, fungal, or parasitic infections may require antiviral, antifungal, or antiparasitic drugs, respectively, to treat the condition and the muscle pain.

Medications

Muscle aches are a common side effect of drugs called statins that are used to lower cholesterol. The symptom usually begins within six months of starting treatment and can take around two months to resolve once the treatment is stopped.

Other drugs that can cause muscle pain include:

The rapid discontinuation of antidepressants can also cause myalgia. Rapid discontinuation of steroids in people who have taken them for a period of time can also cause muscle pain.

It is best not to stop any of these medications before talking to your healthcare provider. They may suggest trying a lower dose or different medication to treat the condition or discontinuing the medication.

Fibromyalgia

Widespread muscle pain is a symptom of fibromyalgia. The pain from this chronic disorder is often described as aching, sore, stiff, burning, or throbbing.

The cause of fibromyalgia is unknown but is thought to involve genetics, mood disorders, past diseases, and chemical imbalances that cause a heightened sense of pain.

In addition to muscle pain, people with fibromyalgia often experience sleep problems, fatigue, crawling skin sensations, morning stiffness, impaired concentration, and anxiety.

Treatment may include antidepressants, physical therapy, and other complementary and alternative therapies to reduce stress and a person’s physical and emotional response to pain, such as:

Chronic Fatigue Syndrome

Chronic fatigue syndrome, also known as myalgic encephalomyelitis, is a disorder that causes overwhelming fatigue that is not improved with rest.

In addition to tiredness and malaise (the general feeling of unwellness), people with chronic fatigue syndrome commonly experience generalized muscle aches, memory problems, sore throat, and feeling dizzy when standing up.

Chronic fatigue syndrome is closely associated with fibromyalgia, with some researchers contending that they are both parts of the same syndrome.

Tricyclic antidepressants may be recommended, and since there is no cure for chronic fatigue syndrome, treatment usually focuses on pain relief, which may include:

• Stretching and movement therapies
• Gentle massage
• Heat
• Toning exercises
• Water therapy
• Acupuncture 

Polymyalgia Rheumatica

Polymyalgia rheumatica (PMR) is an inflammatory condition usually seen in adults in their 60s and 70s. PMR causes morning aches and stiffness in the shoulders, upper arms, hips, thighs, and back of the neck. Fatigue, weight loss, poor appetite, and fever may also occur.

People with PMR often complain of difficulties pulling up their socks or raising their arms above their heads to comb or wash their hair.

The cause of PMR is unknown but is thought to be the result of a combination of genetic and environmental factors.

Treatment may include corticosteroids (steroids), but long-term use of steroids like prednisone can cause serious side effects due to the prolonged suppression of the immune system. Other steroid-sparing drugs like methotrexate can also reduce inflammation and may be safer for long-term use. Monoclonal antibody biologics like Kevzara (sarilumab) may also be an option for some people.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that primarily affects the joints. However, RA can also cause muscle pain.

Autoimmune disorders occur when the immune system inappropriately attacks its own cells or tissues.

Muscle pain from RA is usually felt all over the body. This differs from the joint symptoms of RA, which are typically isolated to specific joints on both sides of the body. In addition, RA can cause a low-grade fever, weight loss, and fatigue.

The cause of RA is unknown, but genetic and environmental factors are likely involved. Treatment may include medications such as corticosteroids, NSAIDs, as well as massage, heat therapy and water therapy.

Lupus

Systemic lupus erythematosus (SLE), also known simply as lupus, is a chronic autoimmune disease that affects nearly every organ in the body, including the skin, brain, eyes, mouth, lungs, heart, kidneys, intestines, and joints.

Muscle aches and weakness are common in people with lupus and are often the reason why a person first seeks diagnosis and treatment. Other symptoms include fatigue, skin rashes, hair loss, headaches, joint stiffness, weight loss, and chest pain with breathing.

Treatment for muscle pain associated with lupus includes rest, physical therapy, medications for pain and inflammation. The pain may respond to steroids or hydroxychloroquine.

Inflammatory Myopathy

Inflammatory myopathies are a group of autoimmune diseases characterized by slow but progressive muscle weakness. Some people with myopathy also have muscle pain or tenderness when touched.

The term myopathy refers to disorders of the muscles of the skeleton. These include myopathies like polymyositis (which affects muscles on multiple parts of the body), dermatomyositis (which causes muscle pain and skin rash), and inclusion body myositis (which causes muscle tissues to clump abnormally).

Treatment for these myopathies may include steroids and steroid-sparing drugs to reduce inflammation.

Thyroid Disease

Hypothyroidism (an underactive thyroid gland) commonly causes muscle aches and cramps in addition to fatigue, weight gain, constipation, cold intolerance, and dry skin. Less commonly, an overactive thyroid gland (hyperthyroidism) can cause muscle cramps.

The thyroid gland is responsible for producing hormones that help regulate metabolism (the conversion of calories to energy) and numerous other body functions. When thyroid hormone levels are too low or too high, they can interfere with the transmission of nerve signals that regulate the contraction of muscles, leading to muscle pain.

Hypothyroidism is treated with the replacement of thyroid hormone by taking a single daily tablet at a dose adjusted to produce normal thyroid hormone levels. Hyperthyroidism treatment may include antithyroid drugs, radioactive iodine-131, or in rare cases, thyroid surgery.

Primary Adrenal Insufficiency

Addison’s disease, also known as primary adrenal insufficiency, is a rare disorder that occurs when your adrenal glands do not produce enough of the hormones needed to regulate metabolism or sexual function.

Addison’s disease is often related to an autoimmune disease that attacks the adrenal glands but may also be caused by injuries or tumors.

Addison’s disease can cause generalized muscle pain, fatigue, nausea or vomiting, darkening of the skin, weight loss, and salt cravings. Muscle pain associated with Addison’s disease is often centered around the legs and lower back.

People with Addison’s disease are treated by replacing the deficient hormones cortisol and aldosterone.

Osteomalacia

Osteomalacia is the softening of bone due to the loss of bone minerals. It is commonly associated with a deficiency of vitamin D and calcium. It is common in older people and linked to certain diseases (like celiac disease) and medications (like anticonvulsants).

People with osteomalacia can have muscle pain from muscle spasms and cramps. They often have aching bone pain and tenderness. Osteomalacia can also increase a person’s risk of bone fractures (referred to as pathologic fractures).

The treatment of osteomalacia often involves prescription vitamin D supplements to slow the loss of bone minerals. You would also be encouraged to eat foods high in vitamin D.

Depression

Depression, while a mental health condition, is commonly associated with physical symptoms such as muscle aches and joint pain. In fact, generalized aches and pains are commonly reported by people with undiagnosed or untreated depression.

While the pain may be psychogenic (related to the mind), there is evidence that the imbalance of hormones that regulate moods, such as serotonin and norepinephrine, may contribute to chronic pain symptoms.

Treatment for the combination of depression and pain may include:

• Cognitive behavioral therapy (CBT)
• Relaxation training, hypnosis, and exercise
• Some antidepressants or anticonvulsants

Rhabdomyolysis

Rhabdomyolysis is a disorder in which muscle tissues begin breaking down and releasing harmful substances into the bloodstream. The classic triad of symptoms in people with rhabdomyolysis is muscle pain, muscle weakness, and dark urine.

There are many causes of rhabdomyolysis, including excessive strenuous exercise, medications, illicit drugs, heatstroke, muscle trauma, and blood clots.

Treatment includes providing intravenous (IV) fluids and discontinuing medications or drugs that may be contributing causes. If left untreated, the accumulation of toxins can lead to acute kidney failure.

When to See a Healthcare Provider

If your muscle pain is worsening or persistent, it’s important to see your healthcare provider for a proper diagnosis.

You should also seek immediate medical care if muscle pain is accompanied by some or all of the following symptoms:

• Trouble breathing
• Trouble swallowing
• Profound muscle weakness
• Stiff neck
• High fever
• Confusion
• Seizures
• Muscle pain that is extreme or sudden

Diagnosis

The diagnosis of muscle pain starts with a detailed history and physical exam. Lab and imaging tests may also be ordered.

Medical History

During the evaluation, your healthcare provider will ask several questions to narrow down the possible causes of your muscle pain, such as:

• Did your muscle pain develop gradually or suddenly?
• Have you undergone any strenuous activities recently?
• What medications are you taking?
• Do you have other symptoms such as fever, headache, or fatigue?
• Are you experiencing muscle weakness?
• Is there any redness, swelling, or warmth around the muscle?

Physical Examination

During the physical exam, your healthcare provider may press on various muscles to check for pain and tenderness (including trigger points). They may also inspect the skin and surrounding tissue for signs of swelling, warmth, redness, or discoloration.

Blood and Urine Tests

Blood tests can be useful in diagnosing certain causes of muscle pain. These include tests called erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) that detect inflammation that can occur with certain diseases or infections.

If an autoimmune disease is suspected, there are blood tests that can check for autoantibodies. These are proteins produced by the immune system that target and attack normal tissues. An example of a test is the anti-citrullinated protein antibody (anti-CCP) assay used to diagnose rheumatoid arthritis.

Thyroid function tests can also check for thyroid disease, while a creatine kinase (CK) test can check for an enzyme caused by the breakdown of muscle. Low blood magnesium may also be associated with muscle signs and symptoms.

Urinalysis is also commonly used to diagnose rhabdomyolysis based on toxins and waste found in the urine.

Imaging

Muscle pain causes can also be narrowed done more through imaging tests. Your provider can use these tests to check for abnormalities in your muscles, including tears, lesions, bleeding, and abnormal growths.

Imaging tests that can be used to diagnose muscle pain include:

• Ultrasound: An imaging test that uses sound waves to create detailed images of internal structures
• Computed tomography (CT): A technology that captures multiple X-ray images to create three-dimensional “slices” of internal structures
• Magnetic resonance imaging (MRI): An imaging tool that uses powerful magnetic and radio waves to create highly detailed images of soft tissues

Prevention

You cannot prevent all types of muscle aches and pains, but you may be able to reduce your risk for certain types, like muscle strains, muscle cramps, and chronic compartment syndrome,

To reduce the risk of acute or repetitive muscle injury:

• Run on soft surfaces, like grass or trails, as opposed to hard surfaces like concrete.
• Wear cushioned shoe inserts.
• Remember to warm up before exercising and cool down afterward.
• Switch to low-impact sports like swimming or biking.
• Stay well hydrated before, during, and after exercise.

Summary

Muscle pain, known as myalgia, can be caused by many different things. It may be due to a localized injury such as a sprain or caused by a localized infection like pyomyositis. At other times, it may be the result of a systemic (whole-body) disease or infection.

The cause of muscle pain may require an evaluation by a healthcare provider who can diagnose the condition based on a review of your symptoms, medical history, lab tests, and imaging studies. The treatment of muscle pain can vary by the cause and may involve everything from prolonged rest to surgery.