Hi ASW2836,
Hopefully you have already read this but post #1 here would be a good place to start and has the basic information, steps, and guidelines that can help you make good choices (and more quickly eliminate some of the worst choices such as chain stores and major manufacturers who are not transparent about the materials they use in their mattresses)…
While I don’t have fibromyalgia … a forum search on fibromyalgia will bring up posts and suggestions from and to other forum members who do.
Some of the better options and possibilities in South Florida I’m aware of are listed in post #2 here.
Phoenix