Problem with raising arms in blender?

You should try using your own body as a reference, if you do the pose that the sim is trying to make you will notice that the shoulder will be straight up, so you should rotate the clavicle bone, that you have selected in the 2 picture a little bit up, and it will already look better

you will also have to keep in mind that the rig that the sims 4 uses is pretty simple, so more complex poses will sometimes look a little weird and there is not much you can do about it