Problem related to CDH?

Hello,

I was just interested in another opinion-my son was born in April with a CDH. He had corrective surgery, took very well to the surgery and has been fine-his last follow up was on August 25-a 4 month checkup- and his pedi said he was doing well. At his surgery follow up they did a chest xray and did a heart echo-everything was normal. There has been something that has been worrying me  though-, I have mentioned it to his pediatrician but she doesn't seem concerned-he tends to cough/choke(but stops almost right away) after eating frequently, not everytime but enough-doesn't seem to be a cold-no runny nose or fever or persistent cough-I do try to sit him up and burp him after feeding but this has been common for him. Also, now he has been making a lot of sounds, but sometimes it seems like he is trying to make a sound but no sound comes out..again not all the time-this has been the last few days or so. I was just wondering if this could be related to the cdh at all or if it sounds like it might be something else or this might even be kinda normal in a 4 month old? Thank you