If I may butt in for you: B complex means a combination of B-vitamins, usually B1, B2 and B12. Careful with B3. B5 if skin is sensitive. B6 if you don't remember your dreams, some say. Since many B complex supplements are low dose, I prefer trying high doses and buying them separately. I did a whole vitamin & mineral supp. regime for 3 months which was sposed to help fibro, but it didn't do anything apart from making some of my bloods rocket (OK: 5mg-B12-injections will do that.)
So whilst that may help some against the fibro-pains, Creola's suggestion is targeting the nerves. For general fibro-pain I'd refer to sunkacola's advice, which I agree with fully.