I had chronic back pain (like, going to the ER because I passed out from the pain intense) and I eventually realized it was all stress related, which explained why PT and drugs didn't help. There is nothing physically wrong with my back at all. It made me feel like a crazy person, but it was relatively easy to deal with. The book Healing Back Pain by John Sarno was helpful to me. It's obviously about back pain but some of the pain principles might apply more broadly.