> What can be causing this knee pain/locking?

What can be causing this knee pain/locking?

Posted at: 2014-06-09 
So about 2 hours ago i was riding my ripstick under a 3 foot table and my knees were bent and my feet were flat on the ripstick and i kinda did like a sharp turn to the right and when i did, i felt a sudden sharp pain in my knee that lasted for about 2 seconds. When i stood up it didnt hurt at all but i could only bend it to about a right angle. As time passed i could bend it a little more and now (2 hours later) i can bend it all the way like my othe knee. There is no swelling or bruises right now but sometims i feel a little sharp pain when i bend it or walk and it has this locking feeling. Should i be concerned and do you think this could be a serious knee injury?