A hard penis indicates that the penis is in an erect condition. Kidney pain is mainly a pain in the lower back, suggesting that the patient may have pyelonephritis, ureteral stones and other conditions. 1. Pyelonephritis: Due to congenital developmental abnormalities of the kidney, stones, trauma and other factors, bacteria, viruses and other pathogenic microorganisms invade the kidneys, inducing inflammation. In the case of erectile condition, it may induce pain in the penis and lower back, which is often accompanied by symptoms such as frequent urination, urgency, and painful urination. After diagnosing the condition, you should choose sensitive antibiotic drugs to fight infection, to ensure that the lesion is completely cured, so as to improve the clinical symptoms. 2. Ureteral stones: The pain is mostly induced by small kidney stones detaching from the kidney and falling into the ureter. In erectile condition, patients may have penile pain, small abdominal and low back pain, etc. Ultrasound can help to confirm the diagnosis, and medication and surgery can be taken to remove the stones, so as to improve the patient’s condition. Therefore, patients with low back pain should go to the hospital as soon as possible to complete the relevant examinations to confirm the diagnosis of the condition before treatment.