Despite all the attention it draws in patients, pain has only in recent years been deemed a subject worthy of scientific scrutiny. “It really was the Cinderella of medicine,” said researcher Clifford Woolf. “Pain was always seen as part of some other problem, whether it’s orthopedic or gastrointestinal or whatever.” Woolf’s own efforts for the past 20 years have been directed toward understanding how pain signals at the site of a wound or infection are received and interpreted by neurons in the spinal cord. For years researchers believed that longer-lasting pain was due to changes near the site of injury or infection. In the inflammatory melee following such assaults, it was thought, immune cells produce a sensitizing substance that keeps local pain fibers in a state of high alert — turning them, in effect, into a “Do not disturb” sign for the affected area. This localized view, it now appears, is shortsighted.