Hi Sharon,
Sorry to hear that after all those years on you are still suffering.
I would suggest that you find a good sports massage therapist. They will be able to provide you what a physio can provide and more. I have seen this problem before and I've found the glutes to be the problem as they can get hypertonic and squeeze the sciatic nerve. You might want to also do some exercises to stretch the periformis (another muscle often associated with back problems and loss of sensations in the leg and feet). Do also some research on Trigger Points. You might have developed secondary problems that can mask the true origin of the problem. (Clair Davies books are very easy to understand and use).
The problem about muscle pain is that it's never where the real problem is. A good massage therapist will help you out with massage and assisted stretches, trigger point therapy, and once you are better you should be given exercices to gain strength in order to support your weak areas.
Good luck
Stef