Why don't pain killers work for me?

It is a good start to exercise, but also ask your doc if there is any sort of underlying factors to your pain. Honestly, (and not to scare you) I went to sick call with low back pain, and when they x-rayed it, they said that I had bi-lateral fractures on my L5 and it was pushed forward in relation to my spine, that and some discs were herniated and one ruptured and the other compressed. So, its in all sorts of ugly looking shape. I am not saying thats what is going on with you, but, after 2 years, I finally got tired of the pain, and asked for a shot that would be more effective, the epidural. Work with your doctor about finding a source and a treatment for the pain. Hopefully it wont require a shot, but, hopefully you will find a way out of it.