I was running through my hair on the back of my head when i noticed there was one small bump. I took a shower after and then noticed there were 2 more bumps. They are not painful to the touch, but only when they are pressed on. The pain isnt very severe, but feels like a small bruise. I was wondering what this was. Could it be due to some kind of viral infection. The previous day, it was windy while i was wearing nothing more than a sweater.