I'm sure there is a simple solution to this but I'm not finding it anywhere. I want to create symmetrical shoulder bones for my armature. So I want to use a fork extrude. As you can see in the image below the fork is on the wrong axis. I know I cannot change the orientation of the axis so I tried changing the orientation of the mesh and armature but no luck there. I have x-axis mirror in tools and axes in armature setting selected. Does anyone know how to re-orientate how these are extruding?
Rigging is admittedly not my expertise, but if I understand correctly, this has to do with unapplied transforms, and the direction the model is facing. You have x axis mirror enabled, but are parallel to the x axis (model facing left ortho view) so are unable to properly mirror to get the expected results.
I would first rotate your model 90 degrees on the Z axis to face front ortho view, and apply transforms with Ctrl+A and you should be able to proceed as desired. See .gif below for the steps: