I have severe headaches that feel like brain freeze without drinking anrthing cold. what could it be?

Probably migraine: Frequently brain freeze occurs in migraine patients, and sometimes the migraines themselves give this feeling. If you have been getting headaches for a while, this is almost certainly the cause, particularly if otherwise normal. You may have some medication overuse/rebound headache as well from taking many otc pain meds. A headache neurologist should be able to help you with the appropriate meds.