Sudden lump below ear...jaw problems for a few years

Hello,

Just today I discovered a hard lump below my right ear, just behind the curvature of my jaw. I've had jaw problems for about three years, consisting of clicking in the jaw, but no pain. The lump doesn't hurt unless I push on it. Haven't slept well for the past two days...hope it's nothing serious. I'm only 18.

Thank you, and I hope someone knows what's wrong.