I'm 20 years old and iv been having this on-going problem. I cant seem to build up the right pec. I am right handed and i would say my right arm and shoulder are stronger. Any suggestions would be great. I would suggest doing more dumbell presses instead of barbell, that will help work each arm separately.
Most people tend to cheat on their weakest side.
This causes unequal growth in muscle tissue. You should switch off barbell to dumbells from time to time to help prevent this. I've worked my way up to 190 in bench press, and do a lot of tricep excersises, but I have noticed that I have been neglecting my biceps, due to not having enough time, or other reasons. Diet will play a large factor in increasing bicep size. Unfortunately, so will genetics.