Every morning when i wake up this week i've had a saw neck causing tension head ache on one side all day why is this happening?

Pillow: Best guess would be a horrible pillow. As a spine specialist i can't overemphasize the importance of a great pillow that supports your neck at night. If someone has no pain, they can get away with a cheapo cotton/feather pillow, but if you have cervical joint pain or other neck pain, you really need to support the neck for the several hours of sleep each night.