Throbbing pain in my head behind my left eye and is getting worse.

You need to be seen: This sounds like it could be a migraine headache but without more information and a thorough exam, there is no way to tell. You should be seen by a physician to make sure this is not something more serious and to prescribe appropriate treatment.

Migraine: If red eye and acute glaucoma is ruled out, it is most probably migraine headache. Neurologist can treat.