NEVER scale armatures in Object Mode, unless you then apply the scale (in Object Mode) by keying CTRL+A => “Scale”. Same applies for rotating. It is also not a good idea to scale, or rotate, a rigged object in Object Mode, unless you apply the scale… blah, blah, blah.
This is why we have Edit Mode - to scale and rotate things… It is advisable to have the armature and mesh at a common origin, but it is not necessary in most circumstances. Having unapplied scales and rotations will always FUBAR things for you. Check the Rotation and Scale boxes in the Object Pane - rotations should be 0 and scales should be 1.