Low back pain on the left side may or may not be a disease of the kidneys. Common diseases related to the kidneys are as follows: the first one, kidney stones, stones in the left kidney often lead to low back pain on the left side. When kidney stones cause renal colic, patients often have unbearable pain, accompanied by nausea and vomiting. Secondly, urinary tract infection, especially acute pyelonephritis, can lead to left-sided low back pain, at this time the patient will have frequent urination, urinary urgency, urinary pain as well as accompanied by fever. Thirdly, common causes such as cysts on the left side of the kidney or tumors on the left side of the kidney. When this cyst or tumor produces compression symptoms, low back pain will occur. Fourthly, non-kidney related diseases, such as lumbar muscle strain or neuralgia, can cause low back pain on the left side.