Suggest Medication For Headache On Right Side,behind The Ears And At The Bottom

Hi,I am 39 years old Female, I have been getting these headaches on the right side of my head behind the ear towards the bottom of my head. Only that spot for about a month now. I was thinking it could be stress but it doesn't seem go away. I take 2 meds one for my thyroid( under active) . My blood pressure is great and I am starting to worry about this new pain. Can you tell me what could be causing it and what I should do. Even when it is not hurting really bad which would be like a stabbing pain it's always there like a dull pain and sometimes I wake up with the right side of my head numb.