Why do people keep asking where I am from even when I am with Black people. They always seem to ask about my ethnicity.?

In Africa they would ask which tribe you are from.

Your ethnicity is the language and culture you were raised in. In your case that could be cockney, brummie, scouse, geordie, etc

Too many people are compulsively nosy

And stick their nose in your business. I

Usually walk away from people I never

Met if they start asking stuff or say mind

Your own business and walk away. Some

Shout excuse me sir, excuse me sir, etc etc

To try and lure me into their scam or play.

I ignore them and walk away. They only

Want to dump their problems on me or

Cause me problems. Limit whom you

Interact with.

LIKELY CURIOSITY...............

That's called "conversation". They're usually doing it in an attempt to get to know you better.