Why "pinch myself"? To see if it's not a dream? Is it commonly used expression?

Native speaker’s answer
Rebecca
Yes! That's right! "Pinch myself" is a common expression to say when something feels like it could be a dream or that it's too good to be true. The idea is that the pain from the pinch would wake you up if it weren't real. It's also common to say to someone, "pinch me," as if asking them to pinch you to see if it's real or not. Ex: I can't believe I'm in Paris. I could pinch myself. Ex: Pinch me. Did I just meet Harry Styles?