I was watching a video interview and met the phrase "I got to say", where got to was translated as must.Why are we not using have to here ,but get, and why is the past form used if we are talking about the present? Thanks
I got to say is a elision of I've got to say. That's the history. Native speakers understand got in this context to mean have got, and therefore must is a proper translation. The past tense is not being used here; it is present perfect. When someone says, "I have got a cold," he means that he still has one. In this case, "I got to say" is "I have got to say", which refers to a present desire.
There's a great discussion on all this here: