Normal pain, “acute pain,” alerts us to injury or disease by sending a signal to the brain, saying, “This is where you are hurt—attend to it.” But sometimes an injury can damage both our bodily tissues and the nerves in our pain systems, resulting in “neuropathic pain,” for which there is no external cause. Our pain maps get damaged and fire incessant false alarms, making us believe the problem is in our body when it is in our brain. Long after the body has healed, the pain system is still firing and the acute pain has developed an afterlife.
