I have the most horrible pain where the back of my head meets w/ my neck. I've tried 1000mg tylenol (acetaminophen) an 600mg advil. No recent injury?

Details. Let your doctor go in detail and decide. There r several possibilities. Do not ignore.
Needs evaluation. This could be a bad pulled muscle or sprain but given the location and the failure of relief with over the counter and home remedies such as heat and stretches i would have this evaluated.