Could be many things. A cyst being top of that list. On my hubs lower back he has a strange, hard, lumpy area and it's def not the same on both sides. He's had it since we were married almost 5 years ago and he's 25 now and very healthy. :) just go see your doctor on Monday for peace of mind and real answers. Have you looked at the lump in the mirror? Is there any redness at all? I had a nassssty acne cyst about the same size as you are describing and it was hard. Not very painful or anything but when I felt it carefully, I could feel a head right in the middle. It wasn't red either, though if it is it almost guaranteed an acne cyst. I couldn't really squeeze much of anything out if it but after a couple if weeks it just shrunk away.