Hmmm... They should, at the very least, have given you one orientation session with a PT to explain the TENS unit and how to use it safely & effectively. I have one, and it's come in handy for some things. Finding the correct location for the 'trodes, and then the correct setting, are both critical variables to efficacy. It may take some considerable time & experimentation. Be patient, try to figure out a logical procedure, and stick with it.

Since learning Myofascial techniques, we probably use them more often than the TENS, but still glad I've got it for the tough cases. For spasms, I was taught to use the zapping settings - they're supposed to jolt the spasming muscle until it gives up and relaxes (and you really know when that happens). I use the buzzing settings for burning/constant pain.

Others may vary.

Doc