My guess on cancer: no, definitely not!
It is good, however, you are having it checked.
I don't understand "behind ear"... is that on your neck, or more up on your jaw?
Can you see it (mirror) or is it something you have to feel with your fingers?
I regularly get lumps in my ear lobes - they are internal "pimples" and always ulcerate in an unpleasant way - mess due to the size, much larger than any surface pimple I have had anywhere else, including those from my teenage years, not that I can remember that far back with much clarity.