At the turn of the twentieth century, radiotherapy became an important tool for the management of pain. The report by Wilhelm Roentgen on December 28, 1895, of a new kind of "ray" can be considered a great milestone in the management of pain. Soon after Roentgen rays, (X-rays), were employed in the treatment of many conditions that are accompanied by severe and persistent pain.

Physical medicine may have actually started with the ancient Egyptians' use of electric fish over painful wounds. Within more recent history, the rapid emergence of physical measures, starting in the nineteenth century, including light therapy, electrotherapy, hydrotherapy, thermotherapy, and mechanotherapy. These measures combined with existing techniques, to relieve pain, ensured that physical therapy would maintain a prominent place in pain management.

Between 1930 and 1945 significant developments occurred in pain management. The French surgeon Leriche, was the first person to identify chronic pain as a disease state. In the early 1930's his classic medical publication The Surgery of Pain, described the treatment of Causalgia and Reflex Sympathetic Dystrophy. In 1943 Livingston, published a memorable book, in which he explained pain mechanisms in Causalgia and there related states. These writings stimulated the study of the diagnosis and relief of pain; and sympathetic-block anesthesia became a popular treatment of pain involving known nerve tracts and pain of obscure origin. Anesthesiologists; Woodbridge, Ruth, Mandle, Rovenstine and Wertheim and many other anesthesiologists popularized diagnostic and therapeutic nerve-block techniques in pain control.