I have pain on right side of head behind my ear. i had my tooth pulled last week, should i be worried or go to the emergency room?

Definitely unusual: after tooth extraction to have headache. It could be mastoiditis, so you should see a doctor for accurate diagnosis and proper treatment.

Behind the ear pain: Probably not related to extraction, but you should call the Dentist that did the surgery for a reevaluation. You don't have an Emergency Room problem. A bit of soreness is not an emergency. You would b e better served by seeing your General Practitioner or checking in at Urgent Care.