Lump in occipital area on the back of my skull?

4 days ago i passed out on the sight of blood bumping my forehead on a statute. the paramedic brought me to the emergency room. I didn't get a concussion but i got stitches and a few shots. They let me go later that night because everything was normal. Now i just have a bump it hurts a little when i play with it right on the back of my skull(occipital area) what could this be? Also. i shaved my head recently causing LOTS of razor cuts on my head, it burns right now. Could this be it?