Superstar Hrithik Roshan who set the cash registers ringing with his action-packed film Bang Bang has to be out of action for a few days after his arm injury. The actor apparently injured his arm while working out in his private home gym. Hrithik was already suffering from pain in his shoulder but kept on going as he wanted to lose a few kilos for his next film. Mohenjo Daro a film by Ashtuosh Gawarikar requires him to look lean and therefore he was working out hard to get in the right shape. But the actor aggravated his existing pain