I can't speak to the disc in your back being completely shot, but what I can talk about is my own history with back issues. I hurt it twice in the past with another company, did the whole physical therapy/etc. At first it didn't really seem to do much, but months later my back started feeling better from the stretching I kept doing after PT as well as core strengthening. Nothing too fancy, just holding a few positions for 45 seconds to a minute at a time. I also started looking more heavily into my nutrition to shave some weight off to relieve a little bit of pressure on my back. Since then, no real issues at all unless I'm sitting in the same spot for hours on end.
If I were you, I'd try out some yoga and make sure you follow the methods as much as possible to try to relieve some of the pressure coming in/out of the PC as well as using the hand rail on stairs to take a little bit off your feet as well. Speaking of feet, keep your shoes in good condition and make sure that the insole of your shoe is right for you. I think most Wal Marts have a Dr. Scholls thing around their pharmacy.
Hope it helps somehow. Back pain blows.