Hey guys, so I've been having a casting problem and I know this is a common problem but there are hundreds of causes for casting therefore I am having trouble trying to pinpoint what is causing me to cast and what will help me. When I strike the ball it sounds good but my 7-iron is literally going 10 yards further than my PW both of which are going less than 150. I can't put any distance on my shots and they all seem to just come out weak and die. I'm only 21 years old and I am really athletic with good flexibility so it's driving me crazy that I can't hit my 7-iron past that dang 150 mark at my driving range. My golf instructor says it's because I'm activating my right shoulder and I need to use only my hip rotation to hit the ball. Problem is the more I trying do rotate my hips the more I cast and my right elbow never returns to my right hip like you see the pros do. I really don't know how to make that happen, I go to the range everyday and that's all I'm focusing on fixing and its not getting any better. Here are a couple of screen shots of what I'm talking about:
and here is a video of my swing (skip to:20 for the swing):
I was wondering if there is anyone who can look at my swing and try and guide me in the right direction. Thanks!