Myalgia is the medical term for pain in the muscles, according to Mayo Clinic. This can develop virtually anywhere in the body, and it sometimes goes away after a couple of days, but it can also last for months. Most people experience myalgia at one point or another.
Myalgia is either local or systemic, which means that the patient either feels it in one part of the body or throughout his entire body. When the pain is local, the most common causes come from overuse, minor injuries, tension and stress. When the pain affects the entire body, the most common cause is frequently an illness or infection. In some cases, a medication causes systemic myalgia as a side effect, as stated by Mayo Clinic.
Some diseases that cause myalgia are influenza, lupus, Lyme disease, Rocky Mountain spotted fever and viral and staph infections. Injuries include cramps, sprains, strains and muscular rupture. Other conditions that may cause myalgia include chronic fatigue syndrome, fibromyalgia, hypothyroidism and rheumatoid arthritis, according to Mayo Clinic. A patient should see a physician if the pain does not go away after a week or is accompanied by other symptoms, such as swelling around the muscle, as this may indicate an infection.