Kidney pain can have many causes including kidney stones, infections, injury, or other medical conditions such as kidney cysts, polycystic kidney disease, or kidney cancer. Common causes are:

• Kidney stones: Sharp, intense pain often in the back or side that may spread to the groin.
• Kidney infection (pyelonephritis): Pain in the back or side, often with fever and painful urination.
• Dehydration: Can cause kidney pain due to waste buildup and increased risk of stones.
• Urinary retention or blockage: Causes swelling and pressure in the kidneys, leading to pain.
• Kidney injury: Due to trauma or sports injuries, causing mild to severe pain.
• Kidney cysts or polycystic kidney disease: Dull pain in the back or side as cysts enlarge.
• Kidney cancer or tumors: Persistent pain that does not improve and may come with swelling.
• Blood clots or hemorrhage in the kidney: Severe flank pain with possible blood in urine.

If kidney pain is severe, persistent, or accompanied by symptoms like fever, vomiting, blood in urine, or difficulty urinating, it is important to seek medical attention promptly to diagnose the cause and begin treatment.