Well other than going visiting a chri....chry......ummm back doctor, you could try what Mr Boo does when his back his bad. He lies on my kitchen floor, which is stone quarry tiles. He reckons the stretching and the coldness of the tiles really help, either that or he's got some kinda weird fetish!
Obviously I mean you lie on your own floor- not mine:-)
Dont bother with your GP, they will just say rest it and give you pain killers, as mentioned above try a chiropractor or an osteopath, and try and get an MRI scan if you can, a friend of mine put off having his bad back treated and ended up with a ruptured disc and 6 months off work!