Golf guru here..
Sounds like you are swinging all arms and all your weight in your set up and golf swing is in your heels and not the balls of your feet as it should be. Try leaning forward which will put your weight on the balls of your feet and keep it there throughout your swing. Next, when you swing back, turn your hips, shoulders, and arms at the same time (synchronized). This wil round out your swing going back and round it out going thru impact (like a half circle). Keep your head still and trust it. Bye bye shanks. let me know if it works...