I have simular proble L5-S1 and most of my pain was a exstreme tooth ache like pain in both my legs switching from leg to leg over the last few yrs.
Here is what I recommend and have done. Find a chiropractor or a specialist that pratices a deap tissue message tech. called "A.R.T" which stands for "Active Release Techniques." here is a website to find someone in your area.
www.activerelease.com These people are what I would call a nerve specialist and within a couple visits you will most likely see some very good results and by the way most health insurance will cover the guy I gone to.
If you don't get relief you may indeed have a disc putting preasure on a nerve.
In my case ART treatment worked on one leg but the other leg I did have back surgery to relieve the pain (6/20/2007) and I can feel my feet again with NO pain in my legs or back. But I believe one of the reasons my back surgery went so well is because of the ART treatment I recieve prior to surgery.
Good Luck and I DO feel you pain
brian
PS prior to this I had several stairoid shots/reg chiro/massage/Physical therapy and you name it I tried it. ART was the best of all consurvitive treatments by far