Left side much smaller than right

[nodiggitydave]

I've had this problem ever since I started at the gym.

I recently swapped over between using bars to dumbells because of it..

The left side of my chest doesn't go as low as my right, and it when I tense it it does something completely different. My left bicep is also smaller. I also think i have a problem with walking in which my left leg doesn't stretch as far out as my right giving my a dodgy walk..

Any ideas?

 

[Selene]

so more sets with the side that is lacking to help build it up to equalize