Hi, My Upper Gums Near The Left Side Of My

Hi, my upper gums near the left side of my nose is real tender, swollen, and hurts to put pressure on it. I don't see any markings that could be an ulcer or abscess, nor does my tooth hurt. I noticed it a few nights ago after I got a headache. Sometimes when I move it throbs but only for a couple of seconds. What could it be and how can I get it to go away?