The more I read this, the more sad I become. I didn't realize that you also kept your sweet baby outside all night too! That really bothers me, so to make sure I understand correctly...Your puppy stays in the yard from before 8am until after 5pm, and may come inside for an hour or 2 in the evening, then back outside to sleep by himself all night?
I am sorry, but that is just not OK to do to your puppy/dog, boxer or not. We are all obviously boxer lovers here, so I will focus on the boxer here. These little guys and gals have such wonderful temperments, personalities, qualities, and love to give you and they can't possibly give that to you that if they are left outside all the time bored to tears. All animals need our companionship, our love, our company, and should not be left out to be seen when you want to see them.
Solution: Go buy yourself a nice crate that is big enough for your baby to stand up in without hunching over, and to turn around in. Teach him that his crate is his safe place, his den, his private place all to him or herself. Find someone, a family member, a neighbor, a kid from down the street, someone to come over once or twice during your work day to let him out for a potty and stretch break, it only takes 10-15 minutes. Is your job close enough to home that you can drive home really quick to give him a break yourself?
Then, go buy yourself a nice big dog bed and put it next to your bed. Let your little guy sleep in the house with you next to your bed, or in the hallway or even in that nice big crate. Even if you have to get up in the middle of the night a few times to give him or her a potty break, it is the committment you made the day you brought that puppy home.
By spending so much more time with your puppy, you two will learn to respect and love each other more than ever thought possible. Also get him/her a lot of toys, hide your shoes, close bathroom doors, block off areas you dont want him/her, puppr proof your whole house, push food items to the back of the counters to prevent counter surfing, ...Everyday will get better and better.