“I have a headache and eye pain, what could it be?”

There is a fairly long list of possibilities, ranging from migraine on up. I would recommend that you see a doctor about this. You don't mention if vision is blurry on that side or not, but if present that would sound more like optic neuritis. A severe headache can cause pain in the eye. You don't mention if there is double vision because the left eye doesn't move as well, but that can indicate that control of the eye muscle is affected. The problem can be a headache, a problem in the eye or tissues around it, in the optic nerve, or the nerves that control eye muscles.

Jennifer Lynch MD, FABSM