(Not to 2sweeties anymore specifically; just general info for people reading this thread)
There is no behavior that I take more seriously than an adolescent male's. Puppies are very easily influenced, but when males hit about age 1 they begin to determine their place and their role within the pack structure. They seek out (and will make up for themselves if you don't provide them with one) a 9-5 job, basically. They need to be very firmly led to whatever it is that you determine is going to be their job, or they will do it on their own. Even submissive dogs will do it; their job may not be pack leader, but it could be "protect everyone from bad strangers" (who could be the kids next door) or "dismantle furniture at night." If you have other dogs, the issues become even more complex because of the dog-to-dog chemistry.
Once a dog hits about two or two and a half, he "knows" his job, and getting him out of that mindset is extremely difficult.
Tiny dogs are often given enormous leeway to be nasty, dominant little sods because the behaviors are on a small scale. They exhibit behaviors that are completely unacceptable, and as a result they become poor family members and will be targets for other dogs (because other dogs don't care that they're only 5 lb; if they see a rude dog, they'll either block or kill it). Don't ever forget that toy dogs are DOGS first--you need to shut down bad behavior and specify other behaviors wisely and proactively.
Poms are very, very common because they're so dang cute. But they are literally arctic (husky) type dogs on a very small scale--and the same cautions apply. I have to say that the Poms I know are some of the most naturally dominant and inconsiderate of leadership dogs that exist--that constant high-pitched barking and complete inability to settle down calmly when people are around are not just value-neutral breed characteristics; they're trying to force you to do stuff when you don't please them. And they don't like it when you're refusing to interact with them, which is why the pacing and panting. Poms need lots of exercise, they need calm, consistent leadership, they need panting, barking, and pacing SHUT DOWN immediately. They have the same ability any dog has to be wonderful, rewarding family companions, but it's a lot of work.