When I stand for a few minutes, say about ten to fifteen, I will begin to feel pain in my right knees and thereafter numbness in the leg from the knee downwards, as if there is no life there again. It will be cold as if not part of my body again, until I sit down for a while and keep rubbing it till I start to feel life again especially in the right knee. I feel the pain even sometimes when I sit driving. Please help me out here! What is happening to me?