I'm a Grade 11 trumpet player in both my school's Wind Ensemble (concert band) and Jazz band. I consider myself playing trumpet more or less seriously since Grade 9, but I've had minor experience before.
I'm not necessarily a new player, yet I always have this problem that none of my other friends have. After playing for a while, only my right check starts to clench up extremely tight and it's hard to play anything higher than a middle C. (I've played up to high C a couple of times, and the G just below high C is usually okay for me to reach).
After around, 20-40 minutes of playing in a band rehearsal, my right cheek clenches up. It's interesting to note that it's ONLY my right cheek, my left one has never been affected. After playing some parts, if I get a break in playing, I would be fine with playing for a little bit, but then the problem reoccurs.
I'm trying to find out how to prevent this. In all honesty, I don't practice as often as I should, but even before with practice I'd have this problem. I believe it might be something with an embouchure, another trumpet player suggested maybe it's even the way I'm sitting during rehearsals, the way I'm sharing a stand and always pointed in one direction etc.
Can anyone provide any assistance in this area?