Child Frequently Holds Breath While Coughing. Is He Having Breathing Trouble?

My son is 4 and a half months old now and he occasionally does this thing, probably nothing but I worry, where he will be breathing regularly and then suddenly stop for a second as if holding his breath before letting out a cough . Its only one cough at a time but sometimes he does it a few times in a row within a minute or so. He started out doing it occasionally but now it seems like it is becoming more frequent over the last month or maybe more. Is my son having difficulty breathing or do all babys do this? Theoretically speaking, I have no proof but would not put it past him, if his father was abusing him in any way and caused difficulty breathing, what exactly does difficulty breathing for that sort of abuse typically sound like?