What Causes Numbing Pain Between The Thigh And Knee?

Hi geoff here. some time ago I was doing a lot of stretching. Sitting on the ground and stretching forward to touch my toes. I was holding the stretch for 30 seconds then releasing. after 3 consecutive days, each afternoon for 15 minutes I couldn`t get up and 2 years later I`m still in a lot of pain.The pain(numbing pain) is mainly down the outside of the thigh and behind the knee (on the outside) and into the upper part of the calf. the longer I stand the worse the pain, until I have to sit and rest. So far the doctors have no answer. I would love some help. email: YYYY@YYYY