Is it possible for too much wax in one ear to cause pain to the other?

No: First of all, wax in the ear canal usually does not cause pain. It is virtually impossible to have wax in one ear cause pain in the contra-lateral ear. See an ENT doctor for wax removal.

Possibly: When ear wax is built up as a large impaction, it can cause ear pain. Sometimes people have trouble distinguishing which ear hurts when there is a significant amount of pain in one ear. You can be seen by a family physician, internist, or an ENT for an ear check and wax removal.