I need to ask about the severe knee pain of my father. He is 51 years of age now, and he faces severe knee pain whenever he sits in a same posture for some time and then gets up. Usually he feels pain at two points, one at lower knee joint, and other at the heel. He also feels pain in the lower spine while turning on either side during his sleep. Normal checkups and x-rays have already been done, where nothing much has come up, just that, doctor said about the decrease in the lower cushion of the knee ball, resulting in friction between the ball and the leg bone. Please suggest something to cure such problem and cautions to be taken now.