Your symptoms are way too similar to mine, they are literally identical except for the fact that I don't ever get pain in my shins or knee. Everything else: bilateral, coming on worse after activity, sitting, achy/sore, tour of my lower body. I do not have your back problems however. My back is completely normal except for an L5-S1 herniation. I had a bad L5-S1 herniation that we identified as the likely culprit and after 6 years finally fused it. Needless to say, in those 6 years I saw 10+ doctors and tried a zillion different treatments. Unfortunately, I'm still having symptoms, although the bone hasn't finished fusing. If it completes fusing and the pain doesn't abate, I'll be exactly in your shoes. My next step is to see a neuro so they can run nerve tests, at this point all I can think of is a damaged nerve. The nerves that innervate the areas that I have pain are primarily the L5 and S1 nerve roots. Have you had any success in diagnosing the problem further, what's your current state?