If you want to research your symptoms on the internet and make your own diagnosis, that's your business. But nobody here can determine what problem you have because we either are not doctors and/or we cannot examine your knee.
If you are concerned enough to ask about the problem, then you should probably try to find a way to get real medical advice. Sorry if you don't have the time or money, but there are lots of possible injuries with knees and no way for us to determine which of them is yours.