Suggest Treatment For A Blocked Nose.

my child is 4 months old since he was born he always had blocked nose he had cold 2 weeks ago and since then i feel the blockage is getting worse specially during the night, i breast feed him, but at night he just take my breast for 2 or 3 minutes and also he is so restless and keep touching his head during sleep, i can hear the mucous behind his nose, i use the saline spray (i don't know how frequent could i use it) and sometimes suction of the nose when he is asleep as he hates it, Is this a matter which could worsen and affesct breathing and threatens life, i stay awake most of the night watching him breathing