Final answer:
Pyelonephritis is an infection of the kidneys that can present with fever, chills, lower back pain, and frequent painful urination.
Step-by-step explanation:
Pyelonephritis is an infection of one or both of the kidneys that can occur as a complication of a lower urinary tract infection. The signs and symptoms of pyelonephritis include fever, chills, nausea, vomiting, lower back pain, and frequent painful urination. Individuals with malformations in or damage to the kidneys are more likely to develop chronic pyelonephritis.