Like many others have said keep a food and pain diary for a month and then compare the two. the days that are really bad go to the food diary and see if there are any connections. Stay away from those. I know a few people that have Fibro. My mom my grandma and both my uncles are among them. I think that I have it starting also.
My mom finds that a water bed turned up nice and high helps a lot for her to sleep. there is something about not getting enough of rem sleep or something because the body is missing something to tell the body to paralys(sp) itself.
There are a couple of people who have gone to a raw food diet with no meat or fish that have found much relief from the pain. The best thing is to go to a natural food store and get a few books and start to read read read up on this. Unfortunately the diagnosis of Fibro is kinda a catch all for wide spread pain that the docs are clueless about. you are your own best advocate in the medical world. read all you can and stay away from all things processed and it should help some.
I being in the beginning stages of it do find that when I work out it helps and staying away from processed foods and sugar help a ton. which stinks because I am a sugarholic. hope that this helps.