Some kids are born with some fluid still left in their respiratory tracts. Most of the time, they will sneeze up the excess fluid within a day or so.
If the kid was chilled after birth, that may also be a cause of the wheezing. Make sure he/she is in a draft free area to prevent pneumonia or other respiratory issues.
If you notice any yellow/greenish discharge from its nose, if it stops nursing, and looks hunched over, you need to give antibiotics asap or take a trip to a vet. A small kid can go down fast and get dehydrated.