For a bad disc you want to do Mckenzie exercises. In a nutshell lie on the floor on your stomach up on elbows or put several cushions under your chest for about 15 min with ice pack over the involved disc. Try doing a search for McKenzie. “Teat your own back” is one of his books.
maxter has a good idea, I stretch daily and I have an inversion table that will stretch the spine somewhat. But the best results I get is hanging from a bar so that my back is straight and my legs are bent and my toes are dragging the ground behind me, I ease myself into this position and concentrate and teach my self to relax the back muscles and I usually get a nice stretch/ spinal adjustment out of it.