Hi. Please don't think that your only hope for your barking dog is a shock collar! Not only is this a bad idea for your little 6 lb dog, just like you are thinking, but there are plenty of positive reinforcement methods that you can use to help your dog to stop barking.
Using a shock collar can be dangerous and cause him pain, fear, anxiety and stress. And it can actually make your dog's behavior worse
as he now has more stress
to worry about (the scary aversive shock collar!)
If a trainer tells you to use a shock collar on this dog, please run
and find a positive reinforcement trainer!! You will get much better, happier, safer long lasting results. It may take a bit longer, but you and your dog will have learned to work through his issues, not merely suppress his issues or scare him into submission.
So in order to help you to stop the incessant barking, can you tell us what he is barking at? When does he bark? Is at people or other dogs? Visitors coming to your home? Post man? Trucks passing by? Inside barking or outside barking or both?
Some dogs do boredom barking bc they are basically bored from not being mentally stimulated enough!
Stress barking is another matter. We can help you with that as well.
If you can reply with more info about your dog's barking patterns, I can try to offer you some helpful suggestions.
Thanks for wanting to help your dog!