If you mainly want to work the muscles with a stim device, there are ones you can buy online like Amazon or many health/medical supply sites.

I have an older EMS (electric muscle stim) and just got a new digital IF stim (Inferential) I use them to help with muscle discomfort/pain.

The digital ones are nicer , you don't accidentally bump the dial on the manual ones and give yourself a jolt. done that..
The IF is less likely to produce the stinging zaps when turned up also.

The IF stim & just bought was 90.00 on Amazon.

If you want to try the various types to see if they work for you, calling various local PT places or chiropractors would be a good way to find out who has & uses them, and to see if you can just get a session or 2 to see if they help or not.