It is possible to have a fever with a urinary tract infection. Back pain and fever cannot be generalized for urinary tract infections depending on the site of infection. Acute pyelonephritis usually presents with back pain and fever, while lower urinary tract infections such as cystitis and urethritis usually do not present with back pain and fever. 1. Acute pyelonephritis: the causative organisms mostly use the urethra to enter the bladder for upward infection, and then reach the kidney through the ureter, which is mainly manifested by the patient’s sudden chills and high fever. At the same time, it can be accompanied by pressure pain in the renal region, cribriform angle percussion pain, etc., and bladder irritation symptoms will also occur. 2. Acute cystitis, urethritis: generally more common in women, such as catheterization, personal hygiene, etc. can lead to upstream infection, the main manifestations include urinary pain, urinary frequency, urgency, burning sensation in the urethra during urination. Low back pain and fever are less common. Once a urinary tract infection occurs, you should go to the hospital immediately and standardize the treatment under the guidance of the doctor.