My right bicep is alot smaller then the left bicep?

my right bicep is alot smaller than my left people describe it as an awkard muscle or abnormal. my left one is nice and big. ik people say the right one if your a righty is naturally stronger so its gonna be smaller but this is different. I have controll over a muscle in between the bicep and tricep in my right arm and not my left (i think its like if how you can put right/left eyebrow up and the other down but not vice versa so you have control of an extra muscle in your right/left eyebrow) i think its the brachilais part of the bicep or around there. so i think theyre smaler because i use that other muscle before i use my main bicep part. so any way i can even it out or if this is some mutation or whatever?