While I was on a long bus ride one day, I got this terrible and sudden block (I think that's what it was anyways) in my right knee. I cannot determine a cause, or even know for sure what it was. But it was massive and almost painful, and all the NEW I knew at that time wasn't seeming to help. I spent about an hour on it, and got the block partially cleared. Over the next few days it faded, but also came back at times.

Anyone have an experience similar to this? Any more ideas on what it might be or what caused it?