What are different ways I can help pinched back nerves, other than stretching?

Core strengthening. Most pinched nerves will heal on their own given enough time, but in addition to stretching, there are some other things that can help. For specific nerve in specific locations, injections can help. Strengthening core muscles (lower back, abs) can also take the pressure off the nerves. Also, remember that smoking decreases blood flow and slows healing - don't smoke or be around those who do.
Isometric. Isometric (push and hold) type exercises for the back include bicycle, yoga, rowing machine, swimming. These reduce the pressure on the nerve, indirectly. Positioning with 90 degrees in knees and hips may help too.