Regards! There is a huge possibility that if your baby is otherwise active, breathing well, playful, gaining weight and passing urine and stools, you might be confusing postural stridor with grunt. Such conditions are physiological because of narrow upper airways which might get clogged with secretions. The condition may be relieved by a thin cloth under the shoulders while asleep and use saline drops to clear of secretions. If any of the above is not a yes, absolute requirement to consult

If grunting, it's a indication of pathology, need immediate consultation with nearest Pediatrician.