Alright, so I have been going to a local pool and doing water aerobics. I try to get there at least three times a week, but sometimes its less. I do the stretches before and afterword but I sometimes get a light pain in my knees. This week however once I got out I was sitting down and it felt almost like my knee had poped out of place. I know it didn't that's just how it felt. Does anyone have any ideas what's going on or what I should do about it?