I recently sprained my knee playing basketball....it sweep up the following morning then I went to the doctor for it. No pain when it happened just the following day, it was stiff and hard to Move. I had mobility at the hospital, could move and bend it find with really minor pain, almost none. I have full mobility now, just water on the knee type swelling still and popping/cracking sounds when I bend it back and forth and on the left side of the knee on my left leg, when I bend it all the way back, there s a little bulge but not painful at all. Should I be concerned?