Increasingly, people suffer from chronic, diffuse pain in their muscles (as opposed to arthritic pain that affects the joints). The pain can range from mild discomfort to severe, debilitating pain that renders the sufferer unable to function in normal, dayto day life. The diagnosis of fibromyalgia — a syndrome characterized by chronic pain, stiffness, and tenderness of muscles, tendons, and joints without detectable inflammation — may be difficult, and may depend on the physician consulted. Symptoms of fibromyalgia, multiple chemical sensitivities, and chronic fatigue syndrome often overlap.
http://charlotte.floridaweekly.com/news/2009/0723/health/015.html