Sleeves Mesh Help

Hello! 

I have been working on this little top for quite a while now, it is a simple off the shoulder top with low hanging frilly type sleeves. Everything is fine except for the sleeves, the UV, weight, vertex (except for one spot on the breast area lol don't worry about that) (: all work fine everywhere but the sleeves. They function normally for the most part. But for the area directly under the armpit is like a dead zone.. That part is like stuck. No movement whatsoever. And the mesh is not completely finished so if you look at it and think it needs serious work, you're right lol. I've been stuck on these sleeves too long to fix the other stuff. 

Here is the images with the issue: Image Front / Image Back
Here is the image of what it should kind of look like: Image (still broken when sim moves arm any direction, it just looked okay with the pose.) (:

Here is the package: Package
Here is the .blend: Blend
Here is the EA mesh I used for UV, & Weight: Image

Any help is appreciated! Thank you so much! ♥

-Chris