What Causes Frequent Yawning In A Toddler?

My 2 1/2 yr old finished a cold very recently(his nose is still a little runny) and for the past few days, he has been doing almost fake yawns. As if he is trying to unblock his ears. So I asked him if his ears felt funny/hurt and he says no... But the yawns are pretty frequent and starting to concern me a bit now.