A blocked nose is very common in young babies .It is usually due to normal mucus that collects in the nose, which is difficult for the baby to clear. No treatment is required if the baby is otherwise well and feeding well. Nasal saline drops works by thinning the mucus . Similarly increasing room humidity by placing an electric kettle with water boiling for 10-15 minutes in one corner of the room where the baby sleeps also is helpful.
Hope this information is helpful.

Hello,

Thanks for posting,

From your description your baby is having the symptom nocturnal orthopnea which at his age is probably due to congenital heart diseases or respiratory infection which will need that the pediatrician evaluates the baby again closely. Imagery studies such as MRI, CT scan, EKG, Heart ultrasound, Chest x-ray will be needed to determine the cause of the difficult breathing.
If after taking the nasal drop and the child still continuous to manifest same symptom then it is advisable that you go back to the pediatrician. Now, before we go any further, you have to make sure that your baby is actually having difficulty breathing as it might just be that you are worrying for nothing and that the baby does not have any problems with her breathing except grunting.

Hope this helps