Since you are suffering from:
a) the worst headaches of your life
b) which you wake up with, and
c) accompanied by nausea and vomiting,
d) neck pain
e) not responding to regular painkillers, you need to undergo a CT / MRI Brain Scan, blood tests, an eye check up (fundoscopy), a specialist's opinion and may be a lumbar puncture
Do you also have neck stiffness
along with the neck pain? Is there any history of fever, visual problems? Is your vomiting projectile?
Only your examination and investigations can link your traumatic head injury
to this condition. As you have these symptoms for a month now without relief, you must seek medical help
as soon as possible.