So after reading about different pinning techniques and locations I came upon some interesting information. Nerves are mostly in the subcutaneous layer but in the muscle there are relatively few. From this it was concluded that rubbing the injection site after pinning is not a good idea since it would push up the oil into the subcutaneous layer.

So I tried it out because I was always rubbing the site afterwards and getting moderate pip the next few days. Messed up 3 times pinning (one of those days) but on the fourth pin I injected 2.4 ml slowly and then cleaned-up without massaging. Success! Leg was the tiniest bit sore, I'm sure from the stabbings lol, but otherwise no pain. Hopefully this can help anyone else still experiencing pain while injecting correctly.

http://www.healthline.com/health/z-track-injection#HowTo5