Headaches are extremely common and only rarely serious in origin. Painkillers are usually quite useful, but can be the cause of headaches when used for a long period of time. Some life modification measures like reducing caffeine, cheese, red wine or citrus fruit can be very useful in migraines.
Visit your local Pharmacist for advice. Perhaps consider seeing your GP or calling 111, depending on severity of pain urgently.
However, where there is a new onset very severe headache “worst headache ever”, “like being hit on the head with a shovel” (often in patients previously not known suffering headaches) you need to call 999.