A two-month-old baby feels nasal congestion while breastfeeding and crying, but breathes normally during quiet play and nap times. Occasionally, there’s a deep breath like a sigh when not asleep. There’s no runny nose, but there’s a white, sticky secretion when cleaning the nose in the morning. The baby doesn’t have a fever and coughs occasionally, sounding like a choking cough. Is this a cold or physiological nasal congestion?