A migraine is a result from a combination of blood vessel enlargement and the release of chemicals from nerve fibres that coil around these blood vessels. During the headache an artery enlarges that is located on the out side of the skull just under the skin. This will explain the pulsating feel in that some people will feel.
This causes a release of chemicals that cause inflammation, pain, and further enlargement of the artery. It also happens that females are more likely to suffer from migraines. This can be caused buy menstrual cycle fluctuations and also birth control pills or hormone fluctuations during menopause.
A migraine headache causes the sympathetic nervous system to respond with feelings of nausea and vomiting and in some cases diarrhoea. This response delays the empting of the stomach into the small intestine. This can be dangerous as it affects absorption since most of it occurs in the small intestine.
A migraine also decreases blood circulation and these results in cold hands and feet. It also increases sensitivity to things like light and sound. Some people may even find it very difficult to move and feel that motion makes the pain worse.