http://www.prohealth.com/fibromyalgia/library/showArticle.cfm?libid=14402&B1=EM031809F The more recent research also suggests disfunction in the hypothalamus.
Recent research on pain responses in FMS patients has shown that the brain and chemical responses are different in FMS patients to non-FMS patients when pain stimulus is introduced. However all the studies that have taken place showing this ahve been small scale. On the other hand there have been multiple researches showing the same thing conducted by different researchers in several different countries