Last year I was doing the P90X exercise program and I "tweaked" my right knee. It was really hurting especially when going up the stairs.
But because I hate going to doctors I just did some stretches and took it easy. However, it wasn't really helping. The next day I was out for lunch with a friend of mine who is a Chiropractor and as we were leaving, he saw that I was limping slightly on one knee. He took me up to his office and did a tiny adjustment on my NECK.
I left and my knee wasn't hurting at all anymore. He also taught me a few stretches I can do on the knee, but it was so weird that it was problem in my neck, not my knee. It was such a weird experience. I wrote about it on my Blog here if you want more details:
How I Fixed My Knee | ♥♥♥♥♥♥♥♥♥.com