I have a dull ache on the right side of my head, its very strange cause my left side is totally fine, when I brush my hair or even if my cover rubs my head it hurts, the top of my head and neck are the most sensitive. Any idea what would cause this?

The trouble with dull aches and sensitivity like this is that is can be 'nothing' and will go away on it's own, maybe a pinched nerve from a sore muscle, or it can be 'something' that turns out to be serious. And we know nothing about you in general. So all you can do is a bit of wait and see while you get a doctor's appointment.
I would wrap warm towels around your neck, and get massage of your neck, back, and shoulders.