I agree with what you have said. I went to one physical therapist who uses alternative methods and he thought my gut felt a little puffy (I am thin) and suggested I go to an allergist to get tested for what foods I may be allergic to. He said 'if you have inflammation in one part of the body, it will be hard to heal inflammation in another part of the body'. I didn't go to the allergist, however, because it would have cost at least $400 to go through the testing. Plus (even though I do think I am allergic to some foods), I thought it was a long shot in healing the pf, but maybe it's not such a long shot afterall.
I also agree that a rheumatoid factor may be involved. Some days I feel like I was hit all over with a 2 X 4 and maybe that reflects some kind of autoimmune response. I also think that chemical sensitivity can be a factor for some people, but I realize that is considered a far out idea.
Keep us posted on what you learn.