Bladder may also produce low back pain, and the causes of its pain include: 1. Invasion of ureteral orifice caused by bladder cancer can cause narrowing or obstruction of ureteral orifice, at this time, different degrees of hydronephrosis will appear, and when the degree of hydronephrosis further aggravates, patients will have low back pain. If bladder cancer invades bilateral ureters and causes bilateral ureteral orifice stenosis, it can cause bilateral low back pain, and at the same time, it can be accompanied by the change of urine volume reduction. The pain is often more severe and belongs to moderate cancer pain or above, and it will gradually increase with the progress of bladder cancer, and sometimes even pathological fracture may occur. 3. When bladder cancer bleeds and necrosis, combined with infection, cystitis or pyelonephritis may occur, both of which may cause low back pain, and the symptoms of low back pain can be relieved or disappeared after anti-infection treatment to cure the inflammation.