The body typically compensates in a predictable way when dealing with muscular imbalances.

For example, if you have injured your right shoulder and the muscles are tight and pulling in that region of your body,  likely you could compensate by the muscles in your left low back tightening to create a balance in the homeostasis of the muscles.

It is important that your muscular imbalances be addressed appropriately. Both sides of the body will have different muscles that are tight and more time will be needed for these areas during your session. The same less affected muscle on the opposite side of the body will likewise need less work. 

Think of it this way, if you have a scale that is imbalanced because there are 3lbs on one side and 6lbs on the other you will maintain the same imbalance if you remove two lbs from each side.

And that is why inequality equals balance in the math of Massage.