IGF DES injections

Silly question perhaps: When injecting IGF DES do you need to do it at a specific part of the muscle like insertions or heads or anywhere in the muscle is fine? how much does that bitch hurt in the unusual spots (unusual for me anyway) like pecs, bis, tris, lats and traps?

does the same apply to MGF?

Pecs tris and lats are painless but lats are hard to reach if you have a big chest

Traps sting a bit for me and biceps kinda feel weird/bad after injects

I'm gonna be trying mgf in arms quite a bit during pct so I'll have to get used to that lol