How would you hope to learn what your job is called? Might it be on the job advert? Possibly when you send for further information? Maybe even at the interview? Maybe in a letter after you’ve been appointed or written on your door or on your ID badge? It could even be raised in a discussion with your boss.
I’m not bitter 
But I think I found out what my job title be (and I don’t think I like it very much!). Where did I find it?
The fount of all vital, corporate information. I found my job title in the school’s internal telephone directory.
I now know what I’m called – and will it make much difference to what I actually do? I hope not.
(I n practical terms I think I might stick with the title teacher.)