Need some advice - Self Soothing

Hi All -

My boy is just shy of 5.5 months and we are working on transitioning him to his own room in just a few weeks. At 2 months he slept through the night - but since he turned 4 months that all went out the window. He wakes 2-4 times a night to breastfeed. The Pedi tells me it has a lot to do with me going back to work p/t and he wants to be soothed by me and my boob. Well, my question is, what techniques did you mama's use to teach your babe's to self sooth? He never took to a pacifier and he cannot sleep without being swaddled. We have tried letting him cry after checking/changing his diaper. I really don't mind giving him the boob a few times a night if he is hungry, however I want to be able to break him off before he falls asleep. I know he isn't eating due to hunger, rather more for comfort. Thanks!