Sounds like your dog has seperation anxiety. Start by ignoring your dog about 10 minutes before you leave and about 10 min after you get home. Don't make a big deal out of your coming or going. When you get home he will probabally try to get your attention. Ignore him. It will be hard, I promise! When he calms down, then greet him calmly.
Second, do you give him lots of tos to play with? Maybe a Kong with PB in it to keep him occupied?
When you are home with him, wear him out!! take him for long walks, play with him, get him pooped!!!
One other thing to try, maybe some background noise, like TV or Radio?

Welcome to Pet talk and good luck!!!