Today and yesterday I had to go to work : the pain came back, but I must say that the moment of respite I had means that the method is working for me, at least in part. Should I wait, should I have more sessions, should I have more rest? I don't know yet, we'll see what the future holds.
I think you'll see some changes for weeks to come and/or you'll get organized at a new level. Perhaps exercises or other physical therapies might yield better results. After a month or so, you can have another session and/or new things or tension points could be searched. We'll see.
What is interesting is that you had an appendectomy scar that even though is old, it does relate with back pains:
If one lifts up the bedsheet with two fingers just an inch or so, there will be wrinkles running all across the sheet to the periphery of the sheet, displacing the edge of the sheet sightly. Therefore, the scar of an appendectomy can tug on the fascia of the abdominal muscles which have continuity with the muscles of the back and the ligaments of the sacroiliac joints.