Definitely get it checked out by a doctor. They might recommend rest, some kind of support/brace, therapy, surgery or nothing, but at least you'll have some peace of mind. I did a lot of bike freestyle, skateboarding, water & snow skiing, MX and other body consuming sports when I was younger. While I got concussions, cuts, bruises, lots of roadrash, sprains, and a mangled finger or two, I never had what I considered to be serious injuries. Years later I have an ankle that goes bad on me once or twice a year and other joint pain that probably is a result of accelerated wear & tear as a kid. Not that I wouldn't do it all over again. If the pain hasn't gone away on its own and is getting worse, go see the doc.