I love pinning delts and they are the eaisest and most pain free location for me.
I have wide shoulders and have no issues aspirating. Try this:
Instead of standing/sitting upright when you do delts, try standing, but leaning over as if you were going to touch your toes with both arms. Let your shoulders slouch. Your lateral delt will rotate a bit forward giving better access and you should have no issues reaching to aspirate. It also takes all the tension off the delt muscle so its totally relaxed and the pin slides right in.
It may take a try or two, but once I got it doing it this way its been cake. You can also do a variation of this by squatting down and bracing the pinning arm on your thigh/knee. Takes the tension off and eaiser access. Good luck.