PE2 IM: shoulder pain on descent

I have a problem with shoulder mobility so PE 1 & 2 iM's are good for me. Been stuck on the latter for quite a while now. I started out with an 8lb bar and a very wide grip and developed that ROM. Then I moved to about 2lbs and started narrowing my grip.

 

I'm almost at shoulder width, but lately I experience a lot of pain in my right shoulder when I'm descending after the 10 second hold. It definitely feels like bad pain, has made an appearance more than once, and I'm not sure if I should stop or the proper way to deal with this.

 

It feels like it's localized in the rear delt.

it wouldn't surprise me if your pec minor was a little bit too tight. i'm working on that right now because even when I do reverse plank movements where I push down and extend, I get a wierd nerve type feeling in my armpit near the rear delt. 

How many times do you train?