Need help with bones in blender

[IntrepidNeon]

https://steamuserimages-a.akamaihd.net/ugc/975477922434742543/EAD344908DCD05ED746615F6C6D676D613298D30/ For some reason when repositioning bones to fit the model this always happens to the bones i fit (the arms), textures arent an issue i just made a dumb mistake there but why does moving bones to fit the skeleton break the model so bad? and how do i fix it?