For a couple of years I have had numbness and tingling in my right foot. About a year ago I started having some pain in the back of my right leg, behind my knee. Now I've noticed that if I have to get on my knees - (example, if something rolls under the table and I get down to pick it up) I get a burning sensation in the front of my lower right leg, right below my knee. I have no idea what is causing any of this. Can anyone make a suggestion?