Does a guy realize when he has a boner and does it hurt?

???

yes they realize

I have heard that it sometimes hurts when it gets really hard, but not often

yes, it gets twice as big as when they don't have a boner, sometimes longer, just depends.
It almost never hurts, and if it does, it's not really pain, it just feels like its kinda stretching.

Yes and sometimes.

my boners never hurt unless it is pressed wrong in my pants if I get an erection with my pants on of course.

ya we can fill it getting hard nothing like a bad pain though

yea we can feel it but the hurting part depends on how tight your pants r

yes, he does realize it because he can feel it.
But it doesn't usually hurt. But if it does hurt it isnt pain, its the sticking up of the penis. They do sometimes remain in the wrong spot in my pants so it sometimes feels acward.