Hi,
Welcome to health care magic,
It could be
tension headache or migraine.
Do you have any other symptom apart from headache?
Have you tried any medication and if yes, was it relieved by medication?
Tension headache is a primary or simple headache caused by some precipitating or triggering factor which is relieved by OTC analgesics
(ibuprofen,naproxen,
diclofenac) and eliminating this triggering factor.
Tension headache may last for few hours to some days depending on triggering or precipitating factor like heavy sunlight exposure,
sleep deprivation,wrong or uncomfortable posture,eye strains,stress,long working hours in one position etc.
Migraine is a recurrent headache associated with nausea,vomiting or photo-phobia.
Generally it occurs at only one side of head and characterized by pulsating over head and generally not relieved by OTC analgesics.
You are a likely to be having a tension type of headache as it is not accompanied by nausea or vomiting or other symptoms in your case.
Take OTC analgesic which suits you and take bed rest or sleep with
muscle relaxant and antacid if gas trouble.Try to avoid contact with triggering factor (here sunlight exposure).
If it is not relieved in-spite of taking treatment then you can see
neurologist and undergo clinical examination, routine blood investigations,electroencephalogram or CT brain but only after neurologist advise.
Regards,