I recently was on a 9 mile expedition with the Army Cadet force. During this time, my right knee clicked, and has been uncomfortable ever since. (Around a week ago). It hurts at times, and relaxing it then walking around is quite painful aswell. When standing up, it occasionally builds up a pain, like its about to click, then suddenly goes. Walking up and down steps are like painful, within the joints of my knees. My left knee has been playing up as well, but only minor. But on my right knee, there's a unexplained big bruise on the joint. Is this a major problem ? Can you identify the problem ?