My wife got a hairline fracture in the ball of her shoulder joint about two years ago. Unfortunately, it still hurts when she exercises that shoulder, which limits how much she can train it.
If she exercises each shoulder as much as she wants to, naturally the non-problematic shoulder will progress in strength faster, increasing the already-present strength disparity between the two.
The question is: is there anything wrong with that?
In other words, should she train each shoulder as much as she is able? Or is there something dangerous in increasing lateral strength disparity?
The single-arm exercises she does are mostly kettlebell lifts and swings.