From my limited understanding in topping for it, the possible answers are the same as with much of kink:
* define "pain"?
* hell yes, and it's awesome!
* hello no, and it's awesome!
* well, it gets my endorphins going.
* it puts me in sub / bottom space.
* it's proof of my trust in my top / dominant / grand poobah
I know of one person who experienced pain from getting ballbusted, but never felt nausea - just pain, endorphin rushes, and subspace. It's probably different for a lot of people.
Thankfully I don't have those.. But since the quickest self defense technique they teach us when we're young as to fending off would-be rapists is to deliver unto him a swift kick in the "boys"--- thereby pretty much stopping his attack, --I'd say "ball busting" and sexual arousal wouldn't mix for most dudes.