Left ear full, left temple pain when chewing, whole left side of my head feels pressure and occasionally goes numb. been about a month of this. never had allergies in my life. worried about giant cell arthritis but i know im too young? any ideas?

Would see your dentist to evaluate possible jaw issues (TMJ syndrome). If proven, a nocturnal splint may well help. Agree that temporal arteritis is quite unlikely but a simple blood test can confirm or rule out. Uncommonly, some migraine variants might present this way.

3 ideas. See an ENT, an allergist and a neurologist, for focused evaluations.