Toddler has mucus

My son got cold while back since then he has mucus which is not going away its like on and off. He is not bothered because of it. He eats well not coughing 3or 4 times may be in a day that is also i hear the same cough. His nose is not stuffed just he gets yellow/whitish mucus from nose. I don’t understand the reason why its not going away? I heard the daycare babies often get sick. He is going to daycare. And he is one year old. Should i go to pediatrician?