I have had a headache for over a week on the right side of my head that goes from my neck to my eye. Should I go to the ER?

A headache that long is certainly cause for concern. On a scale of l to l0, how bad is it? Is it a nagging pain or a full out pain? In any event, yes, you should get it checked out by your doctor.

Headaches can be caused by a number of things, allergies, high blood pressure, low blood pressure, stroke, anxiety, lack of sleep, depression, so yes, see your doctor and rule out all possibilities.