Masochism is not related to sex
Any desire to have problems or surfer is masochism which seems to overlap with sexual masochism if person is not frigid.

As for your fantasy I wonder if this is just fantasy or real thing with consequences, because being whipped burned and whatever else is not a big deal by itself the question is what happens next during post nut clarity.
Pain will continue for weeks after such treatment when all your arousal is long gone and you are just trying to do some work.
real masochist will enjoy that pain forever because they want to suffer all the time being focused on the suffering.

But if it just fantasy it is hard to tell if it even masochism at all I guess you never had a chance to try it in real life and very possible you are not even into that thing for real but just love aesthetic and concept. I would suspect that you do not even imagine all that experience as pain but rather as something else, maybe those butterflies in the belly ;)