Hi, have you tried taking it a lot slower and a lot more gently? Plus frequent rests? And drinking plenty of water so you stay hydrated? If you've already tried these things I wonder if your PT could suggest some changes or modifications, because it seems to me that you are in too much pain for this to be ok. I recently posted about exercise and got some great responses. I was trying some intro yoga classes and they were too tough for me and left me too achey. Let us know how it goes.
Jan