I am completely recovered now, but how well I remember when just about every day I would get a new pain or an ache somewhere in my body. I would get intestinal spasms ... this one really freaked me out. I would get pains in the kidney region, all through my legs and lower back. Everytime I went to the doctor, I checked out okay.
Benzos can cause pain or spasms from our eyelids to our toes because all our nerves and muscles that had been suppressed by the benzos have awakened, and it is like a firestorm in our bodies. I don't believe that benzos can cause kidney damage per se, but if the pain in your kidney area lasts more than two days or becomes more severe.. please see a doctor.
I wish you the best on this strange and confusing journey. It does get better, and you will recover.