Why do I get a very bad headache at the base of my skull when I sit in a recliner? If I keep my head in an upright position while sitting in the recliner, it doesn't happen, but the minute I lay my head back, the headache starts. I've tried different recliners, and it happens in all of them. Any help would be appreciated.

Only a doctor can answer that one. If the headache is bad & over the counter meds are not helping suggest you see a doctor about it.

Do you have high blood pressure?

Yes, I do have high blood pressure. In fact, I've wondered if it might be related to the headache. The headache at the base of the skull seems to be one of intense pressure, and it takes hours to face once it occurs.