Baseball: my arm hurts?

When your arm hurts in the elbow area minus an injury, you almost always have something wrong with yor throwing mechanics. Make sure you don't drop your elbow below your shoulder when your throwing, get your arm up. Also start a long toss program at 150 feet. As a former Division-1 Pitching Coach and and a Pitcher professionally I always teach the arm coming out of the slot correctly and long toss. It just puts less stress on the elbow. Good Luck!