It's not the pain .. it' snot painful .. it's distracting and annoying.
It won't stay to the side, instead it ends up between .. rumpling up my clothes (not very professional looking to have wrinkled up clothing while waiting on high profile clients) .. and it's uncomfortable to have something wedged between my boobs.
I'm constantly reaching down, looking down, and fiddling with it trying to get it to stay put.
That is why I say try having boobs. IMO, for myself not speaking for every woman, it is more dangerous for me to wear it than not .. because I spend more time paying attention to the seatbelt and not enough paying attention to what's going on around me.