Since 85% or so of people are right handed, R arm assymmetry is very common. Leg assymmetry less so,
might be worth while to get a tape measure and measure the circumference, you may be surprised comparing R/L at the same level. Most people are within a cm or so being the same. As another has commented, not everybody is a R-L mirror image, rib cages especially are frequently out of kilter due to minor curvatures of the thoracic or lumbar spine. Leg lengths can vary a bit, cm not uncommon.
Steve