What can cause a headache across forehead, behind eyes, and base of head, blood shot eyes and sensitive right eye.

Eyestrain or ???: Headache is associated with many etiologies, but having your vision checked, and corrected with bifocal glasses, can remove eyestrain from the long differential diagnosis list. An ophthalmologist or optometrist can screen the eyes for vision-threatening disease, and opticians can fulfill the prescription. If that does not work, make an appointment with a neurologist who specializes in headache.