The common reasons for wanting to urinate but not being able to do so include prostate enlargement, urinary stones, and overactive bladder syndrome. 1. Prostatic hyperplasia: Prostatic hyperplasia is most common in middle-aged and elderly men. The enlarged prostate or prostate nodules can compress the urethra, leading to partial or complete urethral obstruction, resulting in the problem of not being able to urinate when you want to. 2. Urethral stones: Urethral stones caused by various reasons, when the stone is embedded in the urethra, it will lead to urethral obstruction. Urethral obstruction makes the urine discharge in the bladder blocked, or even can not be discharged, which causes the problem of wanting to urinate but can not urinate. 3. Overactive bladder syndrome: when suffering from overactive bladder syndrome, there will be sudden and uncontrollable urination, and often the bladder is completely empty and still have the feeling of urination, the above situation will also cause want to urinate but can not urinate. There are many other reasons why you may not be able to urinate, so you should go to the hospital as soon as possible to get a clear picture of the cause of the problem.