Hey, lately when I practice my drums my left arm (I'm lefty, so the arm that gets the most use) has been hurting me. It doesn't always hurt, but if I cough or lift something quick, it kills me right under my arm, right on the back-inside of the tricep. I'm pretty sure I'm pulling a muscle.

Is there a stretch I can do before I play, or a change in postion or technique I could use? At first I thought it was just because I wasn't used to drumming, but I've been playing a while now and it still happens whenever I play for an hour or so. I hit really hard, but ironically the only wrist or arm pain I get WHILE I'M PLAYING is in my right arm, which I've had no problems with once I switched to a louder snare I didn't have to hit as hard.

I'm assuming you pulled it once and never fully let it heal. don't flex your arms while your playing and don't keep your elbows to high is the only advice I can really give you. Since you use your arms constantly all day (unlike your quadrocepts) there shouldn't be any need to stretch them.

don't you have one of the sickest drummers in new england to ask?

since you mentioned not hitting as hard with a louder snare try adjusting your technique or your grip. using your wrist and fingertips more and your arm less. read up on and practice the moeller technique http://www.vicfirth.com/education/drumset/domfamularo.html