Non balanced muscle mass

First off, I've never had any kind of injuries (except my legs but it's irrelevant).

1. My left hand's bicep is bigger than my right arm's bicep. I can also control the left hand bicep better when I contract the muscle (my bicep gets harder, it's like I can control more tendons or something from the left arm).

2. My right hand's tricep is bigger than my left arm's tricep.

3. My left pec is bigger and harder than my right pec.

All these differences are big enough to be noted by a 3rd person if I flex.

Is that normal? Do other people get muscle mass imbalance too?

I am right handed and it feels weird that my left bicep and pec are bigger.

It's normal. We are more neuromuscularly efficient with our dominant arm, so the opposing arm usually hypertrophies a bit more to compensate. If your dominant arm is bigger that means you're using it too much.

Proper progressions in bilateral work should correct this over time.

Also if let's say when you do pullups your left biceps is stronger,then your right lat will work harder to compensate for the weaker biceps,so imbalances like this develop.With months of consistent training most imbalances are fixed.Also like they said,there is different innervation of the muscles on the two sides.

I dont have any visible imbalances, but my left arm is stronger than my right arm but my right leg is stronger than my left leg.

Hm thanks that makes sense.

mr jones, are you right or left handed?

left handed