Mark Wahlberg worked out intensively and gained weight to play a bodybuilding criminal in new film, “Pain & Gain” — but that wasn’t the toughest physical challenge on the shoot. “The most uncomfortable thing about this movie was having to get a spray tan every week,” Wahlberg told reporters at a Cinema Society and Men’s Fitness-sponsored screening at the Crosby Street Hotel Monday. “[Director] Michael Bay was insisting I be as tan as possible.” The star added the fake-and-bake was administered where prying eyes could see. “I would do it on the balcony of my hotel room, which was on the 17th floor,” the hunky actor said. “You think you’re free of the cameras and paparazzi, and there I am getting photographed in my underwear getting a spray tan. Not a good look for me.” A party followed at Jimmy at the James Hotel.