I am so sorry to hear about your pain in your legs, you must be truly miserable. I don't think, however, that anyone can tell you what medecine you need or even diagnose you based on what you have written.
What you do need is a doctor who is going to fix your problem, not just give you a bandaid which is what the pain pills are. Maybe you can try a new doctor, (younger might be better) and if they want to give you pain pills, thank them sincerely and tell them you will be using them until you and the doctor can figure out whats causing the problem and fix it.
If he/she won't examine your legs, ask for a referral to a doctor who would be the kind to fix the problem.
Hope that helps.