Myalgia means " MusclePain " and is a symptom of many diseases and disorders. The most common cause for myalgia is either overuse or over-stretching of a muscle or group of muscles. Myalgia without a traumatic history is often due to Viral Infection s. Longer-term myalgias may be indicative of a Metabolic Myopathy , some nutritional deficiencies or Chronic Fatigue Syndrome .