I've had a severe headache for the past 9 hours. No painkillers are touching it, the back of my head is so painful. What can I do, I need relief! ?

Go to ER or Urgent . Care. You may need something stronger than using OTC, and should be seen by a doctor. They'll need to do imaging to see if it's something simple related to your sinuses or something else. This requires a higher level of care than home management.