The top of my scalp severely hurts. I have no visible bumps or red marks on my scalp.

Injury? Have you had any recent injury or muscle spasms in your neck? Sometimes severe pain in the scalp can be from pinched nerves in the scalp or neck. It could also be the beginning of shingles (rash not appeared yet) This type of pain is often shooting pain and may feel like electric shocks, burning or throbbing. I would get checked by a doctor for evaluation and treatment.