Myalgia or muscle pain is a painful sensation evolving from muscle tissue. It is a symptom of many diseases. The most common cause of acute myalgia is the overuse of a muscle or group of muscles; another likely cause is viral infection, especially when there has been no injury. Long-lasting myalgia can be caused by metabolic myopathy, some nutritional deficiencies, ME/CFS, fibromyalgia, and amplified musculoskeletal pain syndrome. The meaning of MYALGIA is pain in one or more muscles. Myalgia is the medical term for muscle pain, which can have many causes, from overuse to disease. Learn how to identify, treat and prevent myalgia with Cleveland Clinic experts. Learn how myalgia, or muscle pain, can arise from workouts or long-term conditions like arthritis, and explore effective treatments today.