I've been in the hills

A thing 21 Savage does in order to be alone, and not have to worry about Jake Paul harassing him.

Joe Budden: What do you do in your free-time in order to be alone.
21 Savage: I've been in the hills.

I've been me

This is what you tell people when they try to tell you who you are and they are attempting to get you to second guess yourself.

Leo: "You know you just don't seem to understand what is happening with this. You are acting strange about this."
Leighia: "Leo, I've been me. Don't start that. It won't work. You are sippin on sus and it ain't helping you."

I've been

Not doing good or bad, you're just alive.

"How have you been?"
"I've been"