The possible causes of lumbago and frequent urination in women are as follows: First, acute pyelonephritis. It is mostly caused by infection of the lower urinary tract that spreads to the renal pelvis. After infection, symptoms such as low back pain with chills or fever, increased frequency of urination, painful urination, and urgency can occur, and it is recommended to retain urine for routine urine examination and urine culture to further confirm the diagnosis. Secondly, the presence of kidney or upper ureteral stones can cause severe pain in the lower back with increased frequency of urination, and in severe cases, nausea, vomiting or hematuria, and ultrasound examination of the urinary system is needed to rule out the presence of stones. Third, ureteral stenosis or secondary hydronephrosis can lead to low back pain and frequent urination. Low back pain is relatively mild, with slow distension or dull pain. CT examination of the urinary system or intravenous pyelogram is needed to clarify hydronephrosis or ureter-related stricture disease.