I have a growing lump three inches under collar bone i believe to high to be cancer could it be?

Yes: Better to have any new lump checked out. Also notice how fast it grows the bigger it gets needs a faster diagnosis.

Maybe: You are pretty young to develop cancer. Nevertheless, you should have a doctor check it out.

Get it seen: This is too big to be a normal node. You're wrong about location ruling out cancer. At your age, it's Hodgkin's until proved otherwise.