Dear Bluelizard, hello
You have not mentioned your age or your medical history as some diseases are more common in certain conditions.
Difficulty in breathing and feeling of nasal stuffiness on lying down can be due to Nasal Congestion
Are you having some history of cold
a few days back ?
You can use Antiallergy along with Nasal decongestant as it can be of some help to you.
You should take medicines only under medical supervision. You should cosult an ENT specialist