Hi, the problem we see here is with the skinning of the arm on your model. It looks like there is no smoothing between weights in the Spine - Right Arm area. This kind of skinning will cause problems in any animation that moves the clavice bone (the shoulder). This can be fixed by skinning some of the vertices to the shoulder bone, not just spine and arm, and then smoothing it all out. You can do this in Maya, Blender, 3ds max or any other 3d software that supports fbx and animation.