I have recently discovered that my current playing technique is flawed, according to my high school teacher and my private teacher. I do not know why, but I cannot "whistle" on my trumpet. Whistling is when you just kind of hiss lightly into the trumpet and a whistling sound will come out, and it's not a note. Anyway, I cannot do that and apparently it is needed in order to play in the higher registers. Also, the sides of my mouth never get sore after practicing or playing, as it is supposed to. Instead, in order to play in the higher registers, I use a combination of tightening the center of my mouth and tightening my throat (it's totally involuntary). Also, when my head is directly straight, my embourchure makes it so that my trumpet is tilted around 10 degrees upward instead of the 30-40 degree downward that all trumpet plays do. What can I do? Can I work with this if I want to get better and go pro?