We're all "uneven". because we are one side dominant, we will always be a little stronger and a little bigger on one side. If there is a significant difference, you can always give DBs a try and focus on keeping your movements nice and even.
There is a more uncommon issue in which you have a neurological or muscular problem stemming from a medical issue, but this isn't really something I would consider unless you showed us pics and there were a significant difference and/or deformity.