Severe Headaches, Painful On Moving Or Walking Around, Advised Beta Blockers. Could Blood Vessel Spasm Be A Cause?

hi i have been experiencing severe headaches everytime i get up n walk around,it started yesterday but i have been to the hospital 3 months ago as i was refered by my gp to a neurologist due to severe head pains during sex named cluster headaches he examined me and made afull report to my gp and instructed him to try me with 80 mg propranalol beta blockers if it ever arised again,i have been back to my gp this morning as these headaches that started yesterday are really severe and painfull when i move or walk about. my gp has now prescibed 80mg beta blockers and said they should open up the blood vessels in ur brain that may be going into a spasm and causing the intense pain,im hoping that this will work,i was just wanting to know if this blood vessel spasm is definatly the cause?