I just read this.. Seems there might be even flexibility imbalance:
http://www.t-nation.com/findArticle....5-084-training
#1: Improve flexibility imbalances between sides
I know what some of you are thinking, "Human beings aren’t perfect, so why bother?" Just because we aren’t perfect doesn’t mean we can’t strive to improve our current physical state. After all, we don’t get up in the morning and think, "Gee, my body isn’t perfect, so I don’t think I’m going to hit the gym today."
Just as we should be working to achieve a balance in strength from side-to-side, we should also be focusing to achieve balance in flexibility as well. Flexibility imbalances between sides will typically manifest into bigger problems down the line.
Take someone whose left hip musculature is tighter than his right. Since the left side is tighter, the hips will typically deviate toward the right side on movements like squats and deadlifts. This will put more stress and torque around the right hip joint (or knee, low back, etc.), which will eventually lead to overuse or injury. We can add single-leg strength work to improve balance between sides, but we also need to address the tension/flexibility issues in the left hip if we're going to increase our lifts and decrease our susceptibility to injury.
Here’s where most people go wrong with flexibility imbalances: they train each side with identical set and rep schemes because they don’t want to be "imbalanced!" I’m sorry, but this is totally asinine. If you train in a balanced fashion but are imbalanced to begin with, you’ll be more flexible, but you’ll still be imbalanced!
For that reason, you need to increase the time stretched, frequency, and intensity on the tighter side until it catches up to the good side. This may take a while, but will be worth it when you're training injury-free and making amazing gains all at the same time.