Have a companion can and possibly make things worse. I highly suggest getting a Obedience trainer who has experience in Dog Behavior. As we can all here try to help you with your problem they will be able to actually see the problems in hand and give you the best advice. I can say one thing if they dog is only a house/backyard dog with no Job then he/she will create her own job. Another thing do you crate the dog while you are gone? Well, if no that would be one thing to start with. Let the dog know where his Den/crate is and that the rest of the home is yours and he is only allowed there when he/she is good or when you are home. But again look for a good trainer in your area.