I was kicking a soccer ball around earlier today. When I went up to take a light shot, I felt/heard my leg pop. It hurt a lot, but only for a little bit. I then got up and it felt like nothing had happened. I kept on playing. Later after another shot, I felt/heard the pop again and the pain. I was on the ground for a few moments, but got back up. There was hardly a difference in walking and pain. Writing this now at night, the only thing I can notice is a dull shooting pain underneath the knee/upper leg that hasn't really been an issue. Any ideas on what this could be?