The exact cause of fibromyalgia is not known. Studies show that people with this disorder have an increased sensitivity to pain, so they feel pain when others do not. Brain imaging studies and other research have uncovered evidence of altered signaling in neural pathways that transmit and receive pain in people with fibromyalgia and these changes contribute to fatigue, sleep troubles, and fibro fog issues. Fibromyalgia tends to run in families and genetic factors are likely to contribute to this disorder. Environmental factors also play a role in developing this disorder.