By this do you mean some sort of impact on the knee that caused the initial problem? I don't recall this happening, and in any case I have had this condition over the course of a few years,so I would expect it to have healed, although at first it was relatively mild - i.e. I would only feel it after exercise (a short while after and continuing for a few days) but now I feel it all the time. It certainly hurts if I bang it or put pressure on it now.
I have tried rest, and while that alleviates symptoms after a few weeks, as soon as I try to run it will return. I am resting it completely just now (apart from walking) and then going to try more intensive stretching and strengthening to see if that helps. I won't be doing anything that causes me discomfort in the area... if that's possible.