Vascular causes of headaches. Artwork showing blood vessels (red) and nerves (yellow) in the head, showing how a headache causes pain. The inset at upper right shows a normal blood vessel (top) and an inflamed and expanded blood vessel (bottom). The latter causes pain, transmitted through the nerves (white flashes). When this happens in the blood vessels surrounding the brain (also shown here), it can lead to the throbbing and sharp pains of a headache. There can be a range of reasons for the underlying cause of the headache, but most are treatable with painkilling drugs.