I was diagnosed with femoroacetabular impingement in 2007 or so, had surgery to correct it in 2008, and I've been pain free since then. Do some internet research and check out the yahoo FAI group. No one really knows what causes FAI, but more than likely there are both genetic and environmental causes. There's probably nothing you did on the bike to cause it; you would have gotten it anyway.

Who is "he" that told you physical therapy would help? A physician? I think you owe it to yourself to get a second opinion, by an orthopedist if possible, even better would be a physician that specializes in the hip, which may not be possible depending on your location. I can tell you that physical therapy made my pain worse and I'm absolutely 100% satisfied with the outcome of my surgery.

Feel free to PM me if you want to talk about it some more (or here but I think the topic will quickly lose relevance to this forum). I'm always happy to talk about my experiences.

Mark