If you look around at the settings on your TENs unit, you should see different things, for settings. They control the wave length, some other things. Unless you had it set by a PT or doc, play with them, see if you get some relief. If you are getting twitches, or contractions, something is set too high. Try moving the electrodes around too. Nothing is set in stone with this. I can get 8 electrodes on my unit, and they might be anywhere. I also have a zillion settings on it, and they change all the time too.