Abdomen troubling me while playing Trumpet?

I've been playing trumpet for about 7 years now and in my Marching band we have a show next year that has very high notes( above the staff C D B E notes) and when I practice and play them I hurt in my stomach. Id say I'm a very good player and that has never happened before. I haven't played my trumpet in 1 and a half months. And id say I'm kinda heavy in the stomach area. I weigh 190. The reason I'm telling you this because I don't know if any of these factors are affecting me? And if any of these are could you tell me how I coould fix it? I have band camp in a month really want to know all of my music before then. I am 1st chair by the way.