Urinary tract infections (UTIs) usually cause symptoms such as increased urgency to urinate, inability to empty the bladder or pass more than a small amount of urine, pain or burning when urinating, urine that looks cloudy or has a pink tint, urine that has a strong odor. Symptoms can range from mild to severe. Left untreated, a UTI can spread to the kidneys where it can cause chills, fever, vomiting and pain in the lower back.