I get a throbbing headache after brisk walking (15mins/mile) for over 2 miles. then i slow my pace, but the pain stays until i rest/sleep. concern?

Exercise induced HA: There are headaches that can be triggered by exercise. Possibly the increase in need of oxygen and blood flow or even the motion or movement of the head and neck. I would see your dr. If it persists.

Yes: It is not normal to have a headache after walking at that pace at your age. You should visit the doctor. They also will check your blood pressure.