It was strange, the other night I woke up with a crazy pain in my knee.  I couldn't move it, straighten or bend it.  I had to literally pick my leg up and move it to where I wanted it.  I actually had a dream that my knee was really swollen, so it must have been hurting enough for it to seep into my dream.  So weird.  I woke up and it was fine.  I didn't hurt any that day either.  That happened to me once or twice before.  It's very bizarre.