A clear case of Knee Cancer. The highly trained medics here at Bike Forums can perform the requisite knee-ectomy. Your knees will be replaced with 50-year-old Campagnolo equipment and they will work pretty ok!
Just kidding. Look up knee bursitis.
Personally, I've gone in for physical therapy, and they assigned me an exercise to do before each ride. Seems to help. Your issue is likely different though, and so you should seek more appropriate treatment. For me, I put on an elastic strap that pulls on my tibia while I do a dozen lunges. Don't automatically do that of course - find a proper diagnosis and treatment.