My Objects keep becoming deformed when I rotate the bones

Question

Ive been working on this rig and have set up all of the weights seemingly correct, but everytime i rotate one of the bones, the associated object and its bone stretches and squashes without me being able to stop it

this is how it looks normally:

this is how it looks when i rotate the bones:

Its especially noticeable with the head (this is normal):

this is not (mind the lack of neck, that's for later):

any idea as to how this is happening and how to fix it? Thanks greatly.

Answer 1

It's hard to tell from the screenshots alone, but judging from how the bones seem to get skewed, it smells like non-uniform scaling.

1. In pose mode, select all bones with A ang go in the menu Pose > Clear Transform > All:
2. ↹ Tab into object mode, select the mesh(es) object(s) and the armature, and press ⎈ CtrlA > Apply Scale. You might also want to apply the rotation too if they aren't.