If you push a 1" needle all the way in, so it sits flush against your skin ... and you are STILL not into the muscle, then you are one fat ass mo-fo ... just saying. Rule of thumb, for me, is 1.5" needles, but purely out of preference, no other reason. I pin delts nowadays, and still manage to get the needle in 1.25" ... just the last 1/4 of an inch before it sits flush with the skin. I prefer to get the depot created reasonably deep in the muscle tissue and honestly, cannot say that I ever felt the feeling you are describing. Probably because I have never thought too much about pinning ... and also don't really concentrate on it while doing it ... it has to get done ... so I just go ahead and do it.