Hi, I have self-diagnosed Chondromalacia (Runner's Knee: http://orthopedics.about.com/cs/patelladisorders/a/chondromalacia.htm ) on and off for over a year now. It mostly comes back after high impact activities like jogging/sprinting/basketball etc. Even low pace activity like shooting around with on the basketball court, catching rebounds would bring it up.
The symptoms would be knee pain getting out of seat after sittng for a while, walking down the first few steps down a flight of stairs, walking up stairs, basically, anything that would involve putting most of my body weight on one leg in a slightly bent position.
Here are some of the things I'm going to try to rehab this injury. IT band foam rolling. IT Band tightness can cause patellar tracking issues. This guy explains it better: http://www.youtube.com/watch?v=t32xJspx50o