TENS is short for transcutaneous electrical nerve stimulation. This type of pain therapy provides short-term pain relief. It uses electrical currents to treat the nerves that can cause back pain and other pain. It is a safe, painless therapy, but it has not been proven to always provide pain relief. The treatment may not be right for you, so talk to your doctor about TENS. Follow the links below to find WebMD's comprehensive coverage about how TENS works, what to expect from treatment, and more.