Should I hire a lawyer to apply for disability benefits for fibromyalgia?

I contacted an attorney to see if I would need legal help with applying for disability and they obviously told me that I should hire them, but I just spoke to a person from she S.S. office and everything seemed to go smoothly and if I do hire the attorney they are going to charge me 25% of my check for a year, so I think I'll take my chances without an attorney and if I get turned down then I'll try with the attorney. I am just wondering if anyone has had any experience with dealing with fibromyalgia and disability? any help would be greatly appreciated.