"The pain is in your head," said Dr. Dante Chialvo, lead author of the study and associate research professor of physiology at the Feinberg School of Medicine. "The whole head."
The study showed that people with chronic pain have a portion of the brain that is always active: the region associated with mood and attention. This constant activity rewires nerve connections in the brain and leaves chronic pain sufferers at greater risk for mental problems.
How Chronic Pain Gets Into Your Head - ABC News