I need help with an arm problem going on for 3 months. my arm locks, pops, and cracks. I am 13. My arm all of a sudden can t straighten all of the way. It sometimes locks and stays there for up to 5 hours. My arm is overall ache,but nothing extreme. It is worse with gymnastics, softball, push ups, etc. ( weight barring activities) I haven t seen a doctor, and my arm is getting worse.