Grunting and groaning newborn.

My baby boy is two weeks old and when I feed him or after he grunts and groans, kind of like an old man if I had to compare it to anything. Is there any reason he does this ? He does it when I lay him down to sleep too, it feels like he never gets rest sometimes.

I lay him upright on my chest for about 15-20 minutes after eating to avoid spit up and burp him after nursing every time.