My head hurts, I hit the back of my neck and now it has a knot on the back and the side of my neck.

The back of my head is also swollen and there are bruises. There also is a tiny scar right beside the knot on the back of my head.

My head also throbs and every time I run it hurts, please help me!

This can't be a recent injury if there is already a scar. You need to see a Physician.