Im on my first mastiff, so i dont have a lot of experience, but it seems like none of them like being alone. We started out crate training, but our bedroom wasnt big enough for the expandable crate we had. We gave up an dlet him have free run after a month. The crying stopped, but when left alone he would destroy things. We have now gone back to a crate when we arent home, but hes still free at night. My only advice would be to keep the crate near you. and for the backyard, try working on being out there with him and getting further and further away for short periods of time. Remember, he will grow up and it will get better, hang in there.