What can cause you to have a headache for over a week?
You aren't going to get accurate medical advice on here, consult a doctor. After that, consult a specialist in the matter if its recommended.
It could be anything from a sinus infection to a pinched nerve in your neck.
Well, I don't wanna scare ya or anything....but.....it might be a tumor.....
Allergies, sinus different things. Rarely a tumor
Could be stress
Stress, Depression, Sickness who knows?