my little daughter has the same problem. She is 19 month. You will need doctor prescription to buy some medication called Earwax remover. Put three drops in the little one's ear and flush out with warm water for 7 days. Then the ear wax will become really soft and the doctor can easily remove it.
I didn't remove it myself. I am afaid I gonna hurt the delicate eardrum. Ask the doctor to remove it NOT yourself.