Any suggestions for newborn phlegm in throat.

Hi,Any suggestions for newborn phlegm...my baby is 7 weeks old,she is having phlegm in her throat.she is unable to burp after feeding because of phlegm sometimes she spitting huge amount of milk(like vomiting)because of burp difficulty...we went to hospital n consulted paediatrician...they are not willing to suggest medication for below 6months...they said it will go on its own.any suggestions for medication or home remedies?