3 month old son is coughing so bad that he's gagging?

there's not too much you can do to keep him from coughing like that :[ my son just got over the same thing. his was due to allergies. i let him sleep in his swing so he could be more upright as opposed to laying flat in his crib. i did the vick's and the humidifier. it's really heart breaking. they just feel so awful! the best advise i can give is just love him. hold him and rock him and let him know you're there for him. keep giving him the medicines. try giving him some baby advil. it helped my son. i bet it hurts their little throats & chest to cough like that. i know mine hurts when i get like that. the advil will knock off some of the pain. but it's that time of year when allergies make everybody miserable. i just held my son and talked to him and brushed his hair. that seemed to at least calm him down. a lot of the times he would just fall asleep for a while on my chest. i hope your son gets to feeling better! it's like a whole new baby once they do feel better.