What Causes Pain In Back While Treating Urine Retention?

I recently had a bout with sepsis. Was readmitted to hospital for urine retention and had to be catheterized with over 1800 ml. I worry that it backed up into my kidneys. I have pain in my back constantly. What tests should be done? I have asked for a referral to a kidney specialist but they sent me to a gyno that has training in that as well and I was not happy with the appointment and still have no answers and still feel bad. My urine did not used to have a smell now it does since all of this. I want to know if my kidneys were damaged as a result and worried about my health in the future.