Squat form check and shoulder pain issue

[kidcolin]

Hi Coach,

I've been following SS pretty much to the T since April, though July was a bit of a cluster**** and workouts around the holidays have been somewhat sporadic. Ever since my squats have got to ~285 lbs, I've been dealing with some dull, numbing pain in my right arm. Something feels off just below the shoulder joint, and it makes my whole arm feel sort of dead. It's interfering with my bench and press sessions. In fact my past two bench sessions have been useless.

Anything specific that could be causing this? Should I try widening my grip?

Here's some vids. Any thoughts on the form would be appreciated:

squat - 315x5 (http://www.youtube.com/watch?v=ty-_N_ZkcIM#t=23s)
squat - 360x1 (http://www.youtube.com/watch?v=izfZ4jNmLZ0#t=25s)

After the heavy single (first time doing this) my arms were particularly fried.

[Mark Rippetoe]

Grip looks good to me. Chalk your sweats under the bar to provide some traction so that your arms have less to do. But I see nothing here that would account for a shoulder problem. It could be that a chiropractic consult is in order.