About a month ago, I fell on my knee. It became severely swollen and bruised. It took about two weeks until the swelling was gone. As of this week, there is still slight discoloration from the bruising and it still hurts, I have a knot has formed and makes it very uncomfortable for me to stretch it out. Along with this, I have also noticed that the back on my knee locks and hurts when I stand or try to stretch. Could this be a contusion, or something else?