Kidney And Lower Back Pain Kidney/lower Back Pain?

Kidney/lower back pain? - kidney and lower back pain

My uncle had a bad pain in my lower back and wondered if someone might know. It hurts when it stops, but relaxed a little in the sitting position. She takes blood pressure medication and drink lots of Diet Coke. He is adding water to your diet though. Any idea what might that be? Only a kidney infection or bladder? Unfort not like to see a doctor, has anyone got any information on why your possile pain and what it can do to improve?