You should discuss the results with your doctor with regards to what they mean.
The back pain that you are experience will highly likely be due to the kidney stones and you do need to be under the direction of a urologist. The urologist will monitor your kidney stone progress and may decide to have them removed surgically or get them shattered so that they can come out on their own.
Make sure that you drink plenty of water and never get dehydrated. Your doctor and/or urologist will advise you, but 2 litres a day is usually recommended. I have read that drinking water with freshly squeezed lemon juice will help to dissolve the stones.
Your shoulder pain is likely to be from being tense or simply a shoulder problem.
I too never experienced shoulder problems when I had my kidney stone and I was extremely ill for a very long time with it.
Make an appointment and see your doctor, ask for a referral to a urologist and get the doctor to examine your shoulder with a possible referral to a physiotherapist.
I am not able to give you a diagnoses based on your results.
Have you seen an Endocrinologist?
I suffered from kidney stones and also pain in my kidney areas for many years. I have been stone free for six years now, since I seen the Endocrinologist. He reviewed my blood work and found several deficiencies, like Vitamin D, low Potassium, and high contents of Salt to name a few. He recommended foods to avoid since my stone were calcium acetate formations and some medications.
However, kidney stone are not the only reason for pain in the kidney area. I had other kidney pains from Reno cyst. My kidney doctor said the cyst is common in everyone and normally do not cause discomfort. I had surgery several times and had them aspirated and this released my pain.
I wish you all the luck in finding the true result and treatment that will help you.
If I told you that I could fully understand your test results, I'd be lying so I won't. What I can say something about that I know is having two stones, each 5mm, with one in each kidney. Yes, they could each be causing you pain, but having shoulder pain from kidney stones is something I have never experienced. I have always had pain, some very severe pain, in my kidney area on either side, but that pain has never traveled to my shoulders. That's covering many years and many stones for me personally too. I would guess that your tightening up your shoulder muscles due to kidney pain from the stones could be causing your shoulder pain, but that's just a guess on my part.