My podiatrist advised that if whatever has caused it in the first place has been fixed, it should be feeling a lot better in two weeks. If it hasn't been fixed then it can take a long time (I had it for a year once before seeing a much better pod/sports therapist). Perhaps your orthotics need adjusting, or you need some strengthening/stretching exercises to prevent the problem?
Sounds very much like patella tendonitis...my physio has me doing all sorts of modified squats to improve tracking, and so far it is working well. Quick trip to a sports therapist will confirm the diagnosis and give you some exercises to fix and prevent it happening again.