Allodynia a condition in which an ordinarily painless stimulus is experienced as being painful.
When discussing Migraine disease and other headache disorders, we generally see Allodynia listed as a possible of a Migraine attack. During a Migraine, we can experience cutaneous (of the skin) allodynia. You've probably heard people say that even their hair hurts during a Migraine. That's allodynia. It can hurt to touch your head, brush your hair... for some people, allodynia can affect the entire body for a time, making even clothes or bed linens against their skin uncomfortable.
You can read more about the symptoms of Migraine symptoms in: