The possible causes of kidney pain with blood in the urine are: first, kidney stones, which can cause severe pain in the kidney area. The pain is often severe colic and accompanied by blood in the eyes, accompanied by urinary frequency and urinary urgency and other symptoms, it is recommended to conduct an ultrasound examination of the urinary system to rule out the presence of kidney stones. Second, tumors of the kidney. If the tumor of the renal pelvis is manifested as a blood clot in the shape of a strip with urine discharge, accompanied by bright red hematuria, pain in the kidney area and cancerous fever, CT examination of the kidney is needed to further confirm the diagnosis. If the tumor is in the kidney parenchyma, the hematuria may not be obvious but the back pain is more obvious. When the tumor increases in size and invades the renal pelvis, a large amount of hematuria can be excreted. A CT scan of the kidney and enhanced CT scan are needed to further confirm the diagnosis of renal tumor. Thirdly, if you have acute pyelonephritis, you may also have pain in the kidney area with blood in the urine and frequent and painful urination. Urine culture tests are needed to further confirm the diagnosis of pyelonephritis, which can be accompanied by chills and high fever.