Hi, this is unfortunately a common issue. There are forces between the different body joints, like a rubber leash.
If you draw away the points too far, this may spazzing out. On the other hand, you have the collision and physics that can go mad.
Doing a good pose is always a balance act between the look and the technical aspect.
You may try to set some more of the joints to "on". They are all connected. If you, for instance, turn the shoulder a bit, the ellbow may work more natural. As said above, try to not draw the joints too far away from where they originally were. For collision issues, for instance with the breasts, it is a bit more difficult. There are some ways, but if you want the pose to always work with no hassle, you may better want to change the pose (or breasts) a bit.
Maybe take a close look at some of the very good pose packs as examples, and how the creator has done this.