Lump directly behind left ear lobe. itches and full of pus. popped it 5 times, but is back the next day. sometimes hard, sometimes squishy.

Cyst or lymph node: Either you have a lymph node or more likely an infected sebaceous cyst. Once it pops it will continue to pop. You can try warm compress and meticulous cleaning but it will recur soon or years later. Treatment for the cyst requires cutting it out. It can be done in the office. A general surgeon will have experience with this also plastics and ENT.