I've suffered with lower back pain for years and I am completely convinced that GP doctors know bugger all about it. See an osteopath or a chiropractor. When you feel better, take up Pilates, yoga or Alexander technique (all of which are good for backs). If you know anyone with a Backswing (a device for hanging upside down) ask if you can use it. Whatever you do, DO NOT continue to suffer as you will start compensating elsewhere in your back and you'll end up with far worde problems.

Pat