Help on back symmetry

[sakes]

I have been working out since 2008, and I am currently 21. An issue with my development has been a lack of symmetry (my left low and mid back are significantly larger then my right). This throws off most of my lifts back my left side tends to be a bit strong or more stable, while my right side is lacking. For the last month or so I have changed the grips on my heavy dead lifts (I use to do left over right under). Now that I am use to the changed grip, my deadlifts are back to the usual weight ~405 max. I havent seen any change in my back development or uneven soreness to show that my right back is catching up. Anyone have any advice to what may the issue?

Note: My left arm is ~.25'' bigger then my right.

Thank you for any help.