Muscle pain (myalgia) is a common complaint and is most frequently related to overuse or muscle injury from unaccustomed exercise or work. In these situations the cause of the muscle pain is fairly obvious. However, muscle pain can accompany many other conditions such as infectious disease, autoimmune disease, parasitosis and other problems. Muscle pain may accompany other symptoms such as joint pain (arthralgia), fever, or general ill feeling (malaise). Muscle injury may result from exercise or overuse. It takes about 48 hours for a muscle to heal from minor overuse. Any time that the muscles are sore following exercise, it indicates some extent of muscle damage.

See a doctor if the muscle pain persists beyond 3 days or there is severe, unexplained muscle pain especially if accompanied by other unexplained symptoms.

Some of the most common causes are:

• Tension or stress
• Overuse: using a muscle too much, too soon, too often
• Injury or trauma including sprains and strains
• Fibromyalgia
• Autoimmune disorders such as polymyositis or dermatomyositis
• Infections/infestations of the muscle such as staphylococcal abscess (pyomyositis) or trichinosis
• Generalized infections such as influenza, malaria, Rocky Mountain spotted fever, polio, leptospirosis, rat bite fever, measles or rheumatic fever
• Drugs including amphotericin B, carbinoxolone, chloroquine, clofibrate, corticosteroids or hydroxychloroquine.