I am 27 year old white male. I have had problems with my left knee before, example pop sound with swelling and severe pain maybe 4 to 5 times on different occasions anything from jumping or even just walking over the course of a year or so and I always just thought it was a mild sprain so I just rested, iced and took anti-inflammatory and after a couple of days I felt fine. But yesterday I was just sitting and went to stand up and I almost fell over with severe pain in my knee. I thought it may just go away but it is still highly painful to walk or if I sit for a hour and go to stand up the pain is worst or even just laying down it still hurts but not as bad. The pain is mainly in the front of my knee kind of under the knee and behind the knee and there is a little swelling but not as bad as when I have hurt my knee when it popped. I think there may be something seriously wrong but don t want to spend the money to go to the doctor until I know there could be a problem/what it could be.