Do remember falling on the area repetivitly? My first thought when i read you post was myositis ossficans. This happens when there is repetitive trauma to an area of muscle. Eventually there is changes in the muscle and you get an area of calcification. This could certainly impinge on nerves, resulting in the "funny bone" feeling you discribe.
Your next step should be to see an orthopedic surgeon. They will be able to evaluate your knee, run some tests, and decide on a dx and a course of treatment.
