It’s hard to see what you meant by the figures pectoral bones seem to be reversed. because your picture is on the right side and it is hard to see the shoulders bone. If you really want the bone to behave as you want it to, then you have to re-edit it inside the blender.
At this point, my guess is you are using the genesis 2 character model? Genesis 2 character model has some issues with the skeleton, the best choice here is to either convert it to genesis 3/8 character or you can re-do the skeleton yourself in the blender.