Hi doctors, my 4m old girl baby is making whistling while taking deep breath only when laid down flat. We don't get any sound while pickedup or she's on her side. I have consulted ped today and he examined told that her lungs are clear and gave med for cold.. however, she has no runny nose and no nasal congestion. He advised nasal drops and giving the same. slight cough twice a day. Is this sound normal?! Please tell me as it is very scary