The most common causes of muscle pain are tension, stress, overuse and minor injuries. This type of pain is usually localized, affecting just a few muscles or a small part of your body.
Systemic muscle pain — pain throughout your whole body — is more often the result of an infection, an illness or a side effect of a medication.
Common causes of muscle pain include:
Chronic exertional compartment syndrome
Chronic fatigue syndrome
Hypothyroidism (underactive thyroid)
Medications, especially the cholesterol medications known as statins
Myofascial pain syndrome
Repetitive strain injuries
Rocky Mountain spotted fever