A 3 month child weight around 5 kg after drinking milk he is taking long breath sometimes

A 3 month child weight around 5 kg after drinking milk he is taking long breath sometimes …not regularly and sometimes when he sleep and when he wake up suddenly taking long breath … is that due to fat or weight he bearing…or is there any abnormality with child or is that normal… please any suggestions or how to reassure the parent… Thank you.

In the beginning i thought its inicet questn…