I have some pain and old injuries. Can I follow this program?
Without knowing your history, it’s impossible for me to answer this. However, here’s some info that can help you make a more informed choice. This program offers a lot of options and modifications and was designed with people who have “stuff” in mind, so outside of a private session, this is probably one of the more “history of pain” friendly programs that you are likely to find.
It will include basic exercises like squats, bridges, and push-ups (with all the modifications including wall push-ups), so if you think that you can handle these movements with any weight of your choosing, then the program is probably fine for you to try.
If you have so much pain that you are unable to safely get up and down off of the floor though, then this program is not for you and you should consult a medical provider for diagnosis and treatment.