The knee doesn't seem to have any swelling, but it's very painful to rotate the leg, almost like if I try to turn my leg outward at all, the knee is coming out of place. It's on the outer side of the knee, under the kneecap. There wasn't any pain at the time of injury, and I don't remember exactly when it happened. But I woke up and it was a little sore, then the next day it was worse, and so on. Any ideas? Hard to say without a proper examination. Either it's a ligament issue, meniscus issue, or misalignment of the bones. An examination will help narrow the list down. Consult with an orthopedic doctor. Sounds like you may have slightly torn your ACL or PCL and the more you walk on it you are doing more damage. Get off of it and see the ortho ASAP. it could be a minor tear high on the ACL | 