Even though your hands perform completely different movements when playing the guitar, they still follow the same principles of action of the hand muscles. You need to minimize the muscle tension of the left hand as you did for the right hand. Since in the previous stage you focused on training your right hand, you may have a tendency to overemphasize this hand while playing. If not corrected, this can create detrimental strain on your left hand.
To eliminate this unfavorable possibility, you should again check the posture of your hands. Pay attention to common mistakes .
Is the headboard too low?
Is the headboard too far away?
Is the body too low?