I need some help in mechanics

okay, im a 13 year old kid who has been pitching since i was 7. I can throw a change up that is way slower then my fast ball and i have great control over my change, i can throw a 2 and 4 seam fast ball and have good control, and throw a knuckle ball time to time, but, i think and know that i can throw better and faster, and ive read the pitching articles in the home page, but it really doesnt help. Also, ive told my coaches that i get a sore ar every time i pitch,a nd they look at my arm mechanics and they say nothings wrong, so, if u have any suggestions on how to change the way i throw and some pitching mechanics, i would gladly appreciate it. Thx

To be effective, your change-up shouldn’t be way slower than your fastball. Instead, it should just be a little slower. If it’s too much slower, then hitters will be able to immediately tell that it’s a change-up. Instead, you want them to realize only when they have already started swinging that what you threw is a change-up.

Soreness is normal (pain is not). It implies that you aren’t doing enough throwing (and such things as working out with light wrist weights) between starts.