What is the reason for my client’s back pain? Would she benefit from my adding this to her weekly DSMR session I do?

As you saw intuitively, it is entirely karmic, not a physical problem per se, but it results in severe pain that is dependent on the stresses and strains of body movement and tension. So it is quite real, in being a malady, just not of a definable nature through conventional medical diagnostic means. Doing the DSMR work for her, and including this as a client issue, would add great benefit because, as you know, we would be working with her mind directly to tackle that issue and work on beating back the karmic predisposition that has now erupted in the body and seems like it is here to stay—that need not be the case if we work together in earnest in helping her.