There can be a few reasons why this is happening, but my guesses are a couple of options:
-You overcompensate one side more that the other and I don’t mean during workouts, but rather during your everyday activities.
-Genetics (most likely option)
-Both of the above
There is no way of knowing what the reason is if we can not perform a fitness test/postural assessment and take a look at your workouts. Hopefully someone else here might give you a better answer.