I will tell you from first hand experience. P1s kid (P.5 Version 2) He has pitched since he was 6. He was used at least twice a week during his 13U and 14U years, mainly because of his unhittable curveball. When he got to HS his freshman year he blew his elbow out, broke off the growth plate in his elbow. After surgery , a year off and painful rehab he is back to 100%. His plate is now bolted together so there is zero risk of that happening again so he might be 110% now.
According to his DR the growth plate injury is very common but people ignore it. That pain they get on the inside of thier elbow is not normal, dont let those coaches tell you to ice it and he will be fine. Our DR said if a kid (17 or younger) pitches more than 75 pitches in a week it is too much and they are risking severe damage. He also says kids shouldn't even throw a curveball until college age. Dont let those coaches out there ruin your kids arms for 11U baseball. None of that even counts until they reach High School.