Well, it could be as simple as tension headache, or something more complex like occipital neuralgia, or even upper cervical disc disease.
If it does not go away on its own, have it worked up by a competent spine doctor.
thanks. its been happening for about 4 days now. its never tense (i have really bad muscle tension in back from broken tail bone) Ive thought maybe tension headaches. meds dont help. Thank you so much