Madonna thinks artists deep into their careers should stop if they don’t have anything more to say. But at 56, the singer says she still has things to talk about, and in short, she feels like Pablo Picasso . “I like to compare myself to other kinds of artists like Picasso. He kept painting and painting until the day he died. Why? Because I guess he felt inspired to do so,” she said. “Life inspired him, so he had to keep expressing himself, and that’s how I feel.” Madonna released her self-titled debut album in 1983, and her latest album, “Rebel Heart,” earlier this year. She said the key to sticking around is her continual desire to inspire others. “I don’t think there’s a time, a date, an expiration date for being creative,” she said. “I think you go until you don’t have any more to say.” The pop icon will launch her Rebel Heart Tour on Sept. 9 in Montreal. The tour includes more than 60 shows across North America, Europe, Australia and Asia. “The theme I re...