I also had a herniated disc at L4/L5, and nerve pain down one leg.  I eventually got better by getting to the root of the problem.  I sat all the time and my hips were really tight.  I also biked a lot.  I had anterior pelvic tilt because of my tight hip flexors.  My hamstrings were also tight because they were trying to keep my pelvis from tilting too far forwards.  Since my hips couldn’t move properly, my back had to compensate, i.e. if I had to pick up something from the floor, I had to round my back since I couldn’t squat down with my spine neutral. 

Try and figure out the root of your problem.  A good physical therapist is probably necessary.  From what I’ve read, it seems that discs herniate because of repeated lumbar flexion.  Try and eliminate that where you can.  Use a lumbar support in your car, and try not to sit a lot.  Work on your squat so you can keep your spine neutral when picking something up off the floor.  And what is causing your hamstrings to be tight?  Mine were caused by my hip flexors being tight, which pulled my pelvis forwards, and so my hamstrings were constantly under tension.  I’ve worked a lot on opening up the front of my hips by mobilizing (couch stretch) and not sitting as much, and I always try to make sure I have my pelvis in a neutral position when standing by using my glutes and abs.  Just going after the hamstrings would not have worked in my case.

If you’re up for some technical reading, I learned a lot from Low Back Disorders by Stuart McGill.