If a profession is very pain inflicting is it a sadistic profession or a masochistic profession?

I do not think that an abstract noun, such as "profession" can, in most senses, be described sensibly using either of the words "sadistic", or "masochistic". Those words describe the behaviour of an actor; that is, of an animate, sentient being. So I would say that the person (you) is being masochistic.

Having thought quite a bit about it, it seems to me that the only way in which it might (contextually) make sense to talk about a profession having the qualities of either masochism or sadism, is when it is very clear that you are actually talking about the individuals who are members of the profession. In that way, the usage poses the same individual-vs-collection issue that is raised by whether to treat collective words like "majority" as grammatically singular nouns or as plural nouns.