Yes you do really have to stop training the muscles that are affecting your posture. At least until you correct it.
Swimming can help but it will not solve the problem on its own.
Your play is already affected because you have muscle imbalances. So by stop doing bench presses and bicep curls your play will be much better. Remember, postural strength is always first.
Muscular Strength Athlete and Content Manager
6 Years Lifting Experience
Bachelors in Molecular Chemistry/Biochemistry, Working towards Masters
Lifting Style & Philosophy : Aikido, Energy, Balance, Flexibility, Posture