I just thought of something...yes, the gallbladder/liver is felt in the upper right quadrant, and people feel it in the back, but where I feel my kidneys is right in the waist area on both sides, not in the small of my back where many people say they do.
When I was having an ultrasound once, I was really sore in that area when she was running the wand over it, and I asked her what that was, and she told me kidneys. Then, I noticed that many times after I've done a liver flush, I can feel it in those two areas too, right at the waist on the right side and left side.
I found that drinking Celery Seed Tea after a flush, or taking the Dr Christopher's Kidney formula helped.
I'm not saying that's what it is, but I hadn't thought of kidneys before when you mentioned that.
If you put in a search here on the Liver Flush Forum , searching for "banaba", there is a poster named Philosophical Cat that has good posts on banaba tea for kidneys.