Practise, practise and the soreness will go away. While your sitting on your couch watching your TV work your bow every night, to build your muscles and steadiness.
Do this at your peril! Load the bow with an arrow and sooner or later, either the TV or something (someone) more important dies.
Don't load the bow with an arrow and sooner or later something gets hurt bad. Either the bow blows up with and accidental dry fire and you get lucky, or the bow blows up in an accidental dry fire and you get hurt bad along with the bow.