"A Real Pain" is a new comic drama written and directed by actor Jesse Eisenberg. It's the story of two cousins played by Eisenberg and "Succession's" Kieran Culkin, who take a tour of Poland to honor the memory of their Holocaust survivor grandmother. Our critic-at-large, John Powers, says the movie, which opens this week, isn't just incredibly entertaining; it's one of the best movies he's seen about coming to terms with the past.