Hi There, Im 19 Weeks 3 Days Pregnant, I Have

Hi there, Im 19 weeks 3 days pregnant, I have been under a lot of consistant stress and last night after intercourse I had a sudden pain behind my left ear that then began to run into my temple. There was a very large bulging lump behind my ear that was approximately 2 inches long. The bump has went down but there is still pain to the touch and when I speak too loudly. What is this lump and how can I make the pain subside?