Thanks for your question.
The reasons for your symptoms might include many diagnosis which depends on age of patient, type of
head injury and needs further more history and if needed some investigations to come to a conclusion.
History questions:
1) your age, symptoms like seizures/syncope/ent bleed/bowel or bladder incontenence/projectile vomitings after head injury
2) Is there any blurring of vision
Needs to check your vitals especially
heart rate and blood pressure.
Suppose your age is greater than 60yrs I will consider you having
temporal arteritis and start steroid immediately to prevent
blindness and refer to higher center to take temporal artery biopsy
Suppose you are having symptoms given under point 1 then you i will consider you to have CT brain to r/o bleed.
Other possibilities are Migraine, cluster
headaches, tension headaches.