This rare type of headache doesn’t stop. It causes pain on one side of your face or head. Doctors don’t know what causes this “continuous headache.” But women seem to get it more often than men. With the right treatment, though, most people can get nearly complete relief from the pain.

Reference :by WebMD Medical Reference, Reviewed by Melinda Ratini, DO, MS,https://www.webmd.com/migraines-headaches/hemicrania-continua-symptoms-treatment , july 3rd,2019