Pain in back of head. What to do doctor?

My mother was a low BP patient , had gastric problems and used to have migraine attacks . Then she took fluvol 10 mg for 1 month , did CT scan (report was normal accd to doctor) , migraine went away , but 5 days prior , suddenly her bp increased in night sleeping time and she experienced a throbbing pain in back of head slowly shifting to spine . This happens every night (2-3 nights) while sleeping - pain in back head , not able to sleep, back head shivers and vibrates , and she is taking gas medicines(pan40 and acilok) two times a day for her gastric problems . This head back pain troubles her a lot in night and doesn't lets her sleep . It vanishes after around 1/2 to 1 hour after she keeps her head down continuously . This is happening from last 2 days . Now she has started taking fluvol again from today ... What to do doctor ? Please suggest .. please help ...