I think, sometimes pet parents wrongly mistake coughing with choking, even if it has cold it coughs,.. Does ur dog can able to drink water, If so it's not choking... If it was choking u would have clear reason to mention ie) my dog ate bone then got choked, or else ur pet has went outside had something in mouth then choked...

Hope your pet is doing fine now..if he is choking or trying to wretch just see anything blocking..is he eating fine? Hiccups also common in puppies..pls record a video and  book online/offline  veterinary consultation to understand better .

First, we need to know if something is blocking his airway or if he has coughing or nausea. Based on that, only we can go for his treatment. If there is no veterinary doctor in your place, then kindly go for online consultation and get him checked and get treated.