Chis are lap dogs which doesn't mean they're passive. They're just happiest sitting on our laps being with us. Your little fellow might be used to be active since he was probably in a cage the first few months of his life until you adopted him. He'll start to come around, give him time. Get on the floor with him--throw a ball, tug with him with stuffed animals--just show him that mommy likes to have fun & play too.