Just wanted to know if your trapezius muscles can increase your military press? because they are used in the movement arent they[/quote]
They are to some degree. Then again, most muscles are involved at some point in a heavy military press. If you are doing the exercises mentioned earlier (especially rows and deadlifts), then they shouldn’t be a limiting factor (unless you are prioritizing military press training at the expense of other exercises, of course).
You said that you were only training military press before you got injured. As you were only doing one exercise, I would guess that you were working military press more than three times a week.
This is your main problem, because at the weight you were using, injuries would have come sooner rather than later just by the amount of work you were doing.
Have you looked into Olympic lifting? It emphasizes strength and power, and has plenty of pressing movements to keep you occupied. Olympic lifts will also let you develop strength equally throughout the body, and I think the lack of a base of strength is the main issue here. Potentially dangerous, in fact.
You are (as others have said) extremely strong for your age, but developing all that strength in one exercise is not the way to go.
Have a think about Olympic lifting. It might be ideal for you…