The pain may not be your kidneys, even with only 16% kidney function (which I have) the pain is often dull and not frequent. It may be worth seeing a massage therapist, or chiropractor, I go to a Chinese Medical practice, for back a shoulder therapy, the staff know a lot about the body's anatomy, they did notice I had kidney problems, but I was also very stressed, and my lower back pain was actually cured from the spine, and shoulders. Also reflexology (foot massage) is good for diagnosing different conditions, as crystals build up in areas where the body is experiencing problems, (it's difficult to explain you may need to google it) I really would not worry about it too much, if you have had blood and urine tests it may not be anything serious. Stress makes things worse. Get a second opinion from a different doctor if the therapy doesn't help.