Im a pvssy, I use 25g LOL I personally like to inject SLOW, 2 full minutes and never get any pain afterward.
I have told other to try this. Fill your syringe with water or oil. Point it in the air and push it with the same force you do when injecting. How far does the little stream fly? Now where does it have to go when you are injecting it except blasting into that muscle next to it? why are you sore?
For your bulging disk. ICE and plenty of it. Dont let it deteriorate and get worse. I have had 2 surgeries due to ruptured disk. Not fun.