Most doctors of any sort seem to want a quick fix. Very few take the time to learn about your history, observe your walk, etc. My limited experience with doctors about PF yields these recommendations: 1) $400 orthotics; 2) stretch stretch stretch; 3) pills for pain. Even though I didn't follow that path, I would agree with many people who have suggested tests for stress fractures; if I had known back when I was consulting doctors to ask about this, I would have.
Personally, I suggest bromelain if you haven't tried it already. Its anti-inflamation properties helped me a lot, and I saw results within a week of starting it. Right now I take a serious dosage (500 mg, 600 gdus per cap, 3 or 4 caps per day)-- and I will continue as long as it continues to help. It's not real expensive, you can get 2-day delivery through the Vitamin Shoppe (link from Scott's main document)and you should know in a week or two if it helps.