I love TENS machines. My chiropractor's TENS machine was instrumental in my regaining the use of my right shoulder and arm after a bout of tendinitis. A year later, the same TENS machine helped restore the use of my left arm and shoulder after another bout.
Relief can also be brought about for other physical problems, of course. Arthritis is one of those conditions that may be helped. Joanna Karpasea-Jones shares some very interesting information about the way a TENS machine works, and what it can do for arthritis pain.
The sensations emanating from a TENS machine can range from a hardly noticeable murmur, to a mild buzz, to a tingle, to pins and needles that can get pretty intense. These sensations are caused by electrical impulses.
"TENS stands for Transcutaneous Electrical Nerve Stimulator. Transcutaneous means through the skin. Electrodes are placed on the skin (on the lower back area) with sticky pads. Tiny electrical impulses are then sent through the electrodes. These electrical impulses cause the body to produce endorphins, which are natural painkillers."
https://www.empowher.com/news/herarticle/2010/04/03/using-tens-machine-beat-arthritic-pain