I have never had a bladder outflow obstruction, but my dad tells me that it's quite painful. He often has nights where he has to get up to go to the bathroom several times, and I always feel so bad for him when I hear him stumbling around his room late at night.
He loses a lot of sleep over this. It has to do with his prostate. We don't discuss it in detail, because it is a bit embarrassing to him, but I know that he has been to the doctor several times because of this, and he is on medication for his prostate.
He will go through periods where everything is fine and he doesn't have to get up a lot at night. Then, he will have several nights in a row of bladder trouble. I feel bad for everyone who has prostate issues.