Pain serves a very useful purpose. It is an important symptom for the physician when diagnosing disease. Pain is often thought of as a secondary phenomenon for some sort of bodily dysfunction. However, pain can become the principal problem and very often the only problem. Its persistence over many months ultimately leads to personal, familial and social deterioration. Chronic pain costs industry a minimum of 50 billion dollars a year. One in every 10 Americans will sooner or later suffer from chronic pain. Pain and headaches together account for 30 million yearly visits to health practitioners. Drugs have always been used as the primary source of relief from pain. These may range from aceteminophen and aspirin, to strong narcotics, such as morphine. Drugs, however, are not the final answer to pain relief. In addition to other side effects, 25 percent of patients with chronic pain become addicted, and many go through withdrawal upon discontinuing the pain relieving drugs. Transcutaneous electrical nerve stimulation (TENS) works by providing sensation which interferes with the perception of pain, sometimes providing periods of relief after the electrical sensation has stopped.