I have shot Biceps the outer head was extremely painful and the inner head did not hurt to inject but it hurt allot the next day. Not to much to prevent a workout. I like to inject pecs as there is no pain of any kind for me. I just injected both calves in the outer head yesterday .5 cc each and they are ever so slightly sore today. The up side of the calf was I could feel absolutely nothing while injecting. The left bleed allot though. I like to use quads and pecs those are my favorites. I also use delts but, they are hard for me to reach but there is no pain associated with them either. I can't do a glute I cannot see my ass for my chest so no way to aspirate. I hope these rambling helps.