Narrow your stance and get your knees out more. Shoulder width is a good place to start.
You're rounding your upper back a bit and elevating your elbows to try to make a flat spot, which isn't what we want in the squat. See the angle between your elbows and torso change during the lift? This shouldn't happen. The Book says lift your elbows and your chest when you unrack the bar. You're just lifting your elbows.
Here's an article to clarify. Preventing Elbow Pain in the Squat | Nick Delgadillo