Ever since I passed out playing trumpet, I've developed a habit of closing my throat whenever I ascend. I'd like to place the blame on my tongue rising backwards, which cuts off my air. But even when I set my embouchure and blow through my horn, I can feel the bottom of my throat rise. I'm assuming it's the Valsalva maneuver, but I have no idea how to make it stop. I've tried practicing exhaling and inhaling - I'm able to do it just fine with an open throat. However, when I place my trumpet on my lips, I do it while tonguing no matter what register I'm in, and when I ascend, say anywhere past G on top of the staff, I feel my throat closing, which makes any note around High E or F sound thin. I really need a teacher, but the only one I have access to isn't very helpful with fundamentals, and I'm not exactly financially able to at the moment with college applications going out. Does anyone have any suggestions?