One sided-headaches always call for an investigation of migraine or cluster headaches. You can google these terms to see if either look familiar to you.
You can also google-image "types of headache" for pictures of headache distribution.
I recently started having Left temporal pain, pressure in my Left eye and bloodshot Left eye. This is my second time having these symptoms and both times appeared after a significant amount of stress. I was sent to an eye surgeon who dilated my eye and the only thing he could come up with was Temporal Arteritis, but says that I am just too young to have that. So I was not treated.
Ask your personal MD to refer her to an ophthalmologist Eye MD. You should get the same coverage as when you see any other type of MD. Also rule out sinus disease
JCHMD