I have been getting an odd vibrating sensation in my knee for a few years now and I have a hard time keeping my legs bent for longer than about 20 minutes. Two weeks ago, I fell pretty hard on concrete and since then the vibrations are worse and I can now only keep my knee bent for about 5 minutes without intense stifness and pain. There is still a slight ammount of swelling and it especially hurts when I walk more than a few blocks. I m in seattle and when its cold it hurts more as well. I m wondering if I should have it looked into or what could be the problem. My fiance says I may only have a bone bruise but I have heard they can take months to heal. Is this true? I m a 19, almost 20 year old, female with generally good health and a good weight for my height (5 8 , 147 lbs)