what is this pain in my leg

hello to you... I have a pain in my leg that started behind my left knee and nowafter several years has traveled up to my mid - upper thigh thigh. The more I am on it the more it bothers me and if i massage it at all it aches. the doctors dont know what it is and truly dont seemed very concerned but I am sick of it and it seems to me that nothing should hurt that long without being diagnosed. what do you think?

Unfortunately no one here is in a position to diagnose, but have you sought a second opinion?

I wasnt so much looking to be diagnosed, just wondering if anyone else had experiences