Replying to Knee pain

As soon as I put pressure on my knees, like when im bendig down for an ollie for example it hurts like hell just bleow my kneecaps. Same thing when walkning slowly up stairs. Feels like its a string or something right there. Ive been treating it with antiinflammtion cream but it doesnt help. Ive exrayed my knees but they didnt find anything. (at least not my noob doctor).

I´ve been resting from my training for a long time now but as soon as I try to skate or go to the gym i hurts like hell.

PLease help me. Any suggestions are welcome.