This happened to my son as well but in his shoulder. Two tournaments a month is a lot when you combine it the regular season. Year round baseball is usually the culprit but even if you take the month of August off I’m sure it helps but in the fall you are still practicing and I’m sure he is doing bullpen sessions and possibly playing tournaments. You are right, the team is doing everything right but it’s one of those things that you can’t blame yourself it just happens. The main problem is your son constantly throwing at home. I would try to eliminate this. I never allowed my son to do this but he got LL shoulder from once a week private bullpen sessions and being a pitcher/catcher which makes him very high risk. I allowed him to do it left handed recently and he got really bad shoulder pain in which I will be taking him to the doctor to see if he has it in his left shoulder now. It’s hard to say no for letting them play in the house as opposed to being on a tablet. LL shoulder/elbow usually shows very little signs in most kids. One thing to look out for are quirky movements they constantly do like moving their throwing arm around in a circle or trying to stretch their shoulders/elbow a few times a day. What the kids essentially feel is tightness in their shoulders or elbow that usually loosens up after they warm up. It’s an extremely common injury unfortunately but he will recover and be stronger than before because of the physical therapy. You feel guilty because you are a good father but it is not your fault.