The right side of your brain controls the left side of your body,
so it's not unusual for your right side to be the strong one and
your left to be the weaker side.

As far as being bigger, most of us are born that way, but Did
you ever see a pro tennis players tennis arm? The side most
used is going to be the strongest and most developed.

Ambidextrous I am not. My left side has always been my weak
side, so I was glad when MS chose to strike that side harder and
leave my right side stronger.