I have a lump on top of my head its sore to touch and slight movement of hair also hurts i also have a slight headache. what could be the cause?

Several causes: Any history of trauma to the area, any changes to the skin in the area? any history of other medical problems? Possibilities include a sebaceous cyst, lipoma, occult abscess, inflamed lymph node, or what is called a trigger point. Would have to feel it see the area to narrow that down. Good news, it's very unlikely to be cancer.