Anyone here know how to use a f'in volt/ohm meter?

It’s the plug going to my coil pack.

Looks like this (not my coil pack or my car - just a pic I found on google):

See that plug? That ENTIRE plug (not the wires inside of it - which is why I didn’t understand the bit about using a pin to tighten the pins and got a “” in response) moves ever so slightly while on the coil pack itself, causing the misfire.

What I want to know is…how can I PREVENT it from moving ever so slightly while still being able to remove it if I have to (to change the plugs for example)? Can I just go to a junkyard, cut off that plug, and swap them? Maybe something inside the plug is bent so it’s not ‘locking’ onto the coil pack like it should?