Why does your throwing arm hurt after I pitch?

Answer 1

Lactic acid is actually an energy source when there's not enough oxygen in the body to make ATP. Your arm might hurt because you only throw 30 pitches twice a week and then you go and throw 100 in a game. It could also be that you're throwing all arm and no body. It could also be that you're trying to throw a lot of curve balls. You shouldn't ever throw a curve ball until your arm is developed. There's a place in your elbow that isn't connected through bone and throwing a curve ball can tear it.