The possible causes of back pain and blood in urine in men: 1. Kidney stones can cause pain in the kidney area, accompanied by changes such as blood in the eyes or red urine, which requires ultrasound examination of the urinary system to rule out the presence of stones. Stones in the upper urinary tract may cause nausea and vomiting in addition to low back pain.2. Tumors of the kidney, most commonly seen in elderly patients, can cause low back pain, blood in the urine, and more bleeding, which can cause hematuria or blood clots in the urine throughout. If there are ureteral tumors, stones and other lesions, it can cause water retention in the kidneys and lower back pain, accompanied by hematuria, and may be accompanied by urinary frequency and urgency, which requires ultrasound examination of the urinary system to rule out ureteral tumors and stones.