Is offensive to ask my professor the detail of my grade?

I’m an international student and not familiar with how everything works in american colleges. So here’s what happened:
we did a group assignment, and the professor combined the group assignment grade and individual assignment grades together. Since the group assignment grade is the same, I got different grade from my team member, that means I did bad on my individual assignment. So I asked him about my individual assignment grade and wanted to get some feedback…

this is what I said: Professor, my total grade is different from my teammates’. Since this is the combinated grade, I think I did poorly on my individual assignment part. so I would like to ask about my individual assignment grade.

He goes on talking why our grade is different…however, this was not my question, I asked him again about the individual assignment grade. He said he would send to me later. When he sent it to me, he explained again why the grade is different and sent email to the whole class why this is different and said “please stop asking the grade.” I was talking to him about the individual grade the whole time and asked if there’s problem with my assignment and how i improve etc… I feel little frustated when he sent the email… I only said the grade difference once so he knew why I asked him my individual grade(becaue group grade is the same)… or maybe I shouldn’t say that…I think I made a big mistake…becaues in america I heard people don’t like to discuss about grade.(sorry to say, but this really wasn’t my fault, my teammate asked me grade first, then we had a discussion about grade)

Now I don’t know if I was too offensive and apologize for my bad english.

If the professor have office hours make an appointment and tell “I know I didn’t so great in my individual assignment, Which are your recommendations to improve my grades”.

Definitely…go to the professor’s office hours and say 'I would like to get feedback on what I could improve on for my part of the project. I am not here to dispute it, but figure out what I can do differently".

There are a couple of things that could be going on:

  1. He thinks you are going to argue about the grade. You said you are asking about the grade, not asking for feedback.
  2. You are asking at an inappropriate time
  3. He can’t explain to you what the issue was (which isn’t good)