baby breathing at night

my baby is 4 months he keeps waking up at night because it’s like he can’t breathe through his nose and i wake up and pick him up and he needs his head lifted up. he can’t stay on his back after like 4 am so i have to put him on my chest or in my arms. i’ve tried saline , i’ve tried steam , ive tried humidifier, air purifier , nose frida , breathe frida , vapor drops in humidifier. idk what else to do. hes been doing this for 5 days already waking up all through the night i’m sooo tired at this point.