Hello, Thank you for your question and welcome to Healthcare Magic. I read your query and I understand your concern. Kidney stones and gallstone differ in composition and position in our body. So, a kidney stone is a solid mass made up of tiny crystals. Gallstones are hard, pebble-like cholesterol or pigment deposits that form inside the gallbladder. They can be in different sizes. There can be one or more stones in the kidney or gallbladder at the same time. Both kidney stones and gallstones are often asymptomatic until the stones grow too large. Because of the different position in the body the pain in two cases is different. Kidney stones common symptoms include pain in abdomen, groin or flank, right sided or left sided depending on which kidney is the stone. There might also be blood in urine, nausea, fever and chills in case of infection. Gallstones are usually asymptomatic but in certain cases there might be pain below ribs, back and right shoulder, nausea, sweating, restlessness and fever.Gallstone attacks often follow fatty meals In your case the left sided pain and discomfort in lower back side sugests a kidney stone. I recommend you to get an abdominal ultrasound and it can be easily diagnosed where the pain comes from. Hope I helped with my answer. For further concerns or follow up questions, feel free to write again, I will be pleased to answer you again. Take care, Dr. Artiona