Headaches are a very common condition. Just because they are a common condition does not mean that they are normal. Many times the bones of the neck are locked together and cause pressure to the nerves that go on to the head. Also the small muscles that support the skull, especially those that attach from the neck to the base of the skull can create a lot of pressure on those same nerves.
As you can see in the picture the deep muscles of the neck connect from the small bones of the neck up onto the head. The nerves then pass between these muscles. So even slight increases in muscle tension can cause headache and migraine symptoms.