My little guy (whos 5 and half months old) has his first ear and sinus infection :( but if you look at him, you would not know it, his still talking and laughing alway. Doesnt seem to bother him much.

My first son was the same way, he had double ear infections for a long time before we had his tonsils removed, but we never knew it unless we were at a checkup.

I did read somewhere, that babies that eat from a bottle laying down are more prone to ear infections than those that sit up.  There is something about pooling of the milk in their throat.