Every body is going to react to different things... 

Try it out Hawk and see how it goes... deep tissue injuries take so long to heal... I have used and know people that have used the TENS machine to help with back pain... three said it helped two didn't like it...  I have also heard people talk about the ultrasound machines... some say it is wonderful and some say it isn't any good. 

I hope it helps and does the trick.