Low back pain, low urine output and urinary urgency may be caused by acute pyelonephritis, kidney stones, nephritis and other factors. 1. Acute pyelonephritis: it may be related to lower urinary tract infections, prostate hyperplasia and other diseases. Due to the presence of infections in the kidneys, which cause local irritation, it will cause symptoms such as low back pain, low urine output and urgency to urinate, which may be accompanied by fatigue and fever, and in severe cases, hematuria may occur. 2. Kidney stones: may be related to metabolic abnormalities in the body or environmental factors, kidney stones move downward, may be stuck in the ureter, causing irritation to the ureteral wall, which will cause lumbar acidity, urinary urgency, urinary output, and there may be severe lumbar and abdominal pain, as well as hematuria. 3. Nephritis: may be related to infection, bad habits and other factors, can make the patient appear back pain, low urine volume, urinary urgency and hematuria and other symptoms. Low back pain, low urine output and urinary urgency indicate the presence of abnormalities, and it is recommended to consult a doctor for appropriate examination and treatment to control the development of the disease in a timely manner.