I have and still do use her program.

I have seen her replies to others with the same problem.

It seems we often get too carried away at the beginning and are stretching just a bit too much.

The secret is just to find the smallest sensation of a beginning of the stretch - and hold it there - do not go beyond that slight sensation.

You almost need to close your eyes and really focus on only finding and feeling that.

I admit I had to read her book a few times thru for it all to really sink in.
Plus reading her posts to myself & others on the web.
You can do a search of her name to find more info. I believe she takes questions on her site too.

I think she says if you are uncomfortable or increase of pain or symptoms - rest.
Even if you just do the laying on the floor and relaxing part many times a day
but don't put arms out to any uncomfortable angle- be comfortable and focus on the relaxing part and breathing properly

Then after it calms down
restart and go slow - think baby steps
find that smallest sensation of a tiny stretch only
and then slow go with it