Physical Therapy?

I did a little bit of PT (2-3 month...) for my back just after I got the brace. Now, I have stopped. However, I have noticed that whenever I am not wearing the brace my back hurts really bad. Here is my explanation: when my brace is on, my back does not have to work very hard because the brace is doing all the work. Those muscles go to "sleep". Now when the brace is off, those "sleeping muscles" have to wake up and go back to work but do not have the strength to do this because they are never working. Problem. 

For example, during WWII women stopped wearing their corsets because the United States Government needed all the metal they could get for planes, guns, etc (there was medal "bracing" in the corset that held you up and sucked everything in). When women stopped wearing their corsets, their backs went to mush because they had NO back muscles. could this be happening to me?? (yikes!) 

Do you/anyone you know with a brace participate in PT? If so, is it exercises or something other?