Baby is making whistling sound while laid on back. Checked with ped today. He said everything is normal and nothing to worry as her lungs are clear.however she doesn't have any runny nose cold symptoms or nasal congestion.but why she is feeling diffuculty while laid down on back and making noise. Other than that she is actively playing and screaming. Is it an issue?! Wanted to take second opinion here again.. Doctor has recommended to give her nebuliser.. is it necessary if her lungs are clear or what should i do pls advice