A migraine is not just a bad headache. It is an intense, throbbing pain. Migraines can also cause nausea and sensitivity to light and sound. Most experts agree that migraine pain is caused by swollen blood vessels around the brain and certain nerves in the brain. However, the exact cause of migraines is not known. Migraine drugs cuts headaches short, relieves migraine pain and symptoms, such as nausea and sensitivity to light and sound.