Hi there,
Is it directly behind your ear lobe? Only because I got a small lump there and it came out in response to an infection that I had going on somewhere else in my body, I went to the docs and she gave me anti-biotics which cleared it up, it was just a swollen Lymth ( sp!?!) node, but I would get it checked out anyway at the docs asap so you can put your mind at rest!
P