3 yr old boy, with constant cold, running nose

my 3yr old son gets cold often. which starts with running nose. sometimes followed with fever and/or cough. he doesnt like to use a blanket while sleeping coz of the fear of being trapped in it. but wear sweater and jackets in cold weather. any change of weather starts his running nose. he always has audible breathing, which can be heard easily, as if he was running. closes his mouth on sleeping when he has no cold. but the blocked nose during his cold troubles him at sleep.very active by nature, careless too. eats well.

also, yes. evening and today morning he puked after taking milk. he has little congestion right now, his nose was getting blocked often while sleeping last night. pls help