The use a 60-80ga square needle to get the thick fluid into your shoulder, and that HURTS, with lasting painful side effects and more. Same for Shingrix shots.
I have Type 1 Diabetes, give myself 28 belly-fat shots/ week, but w/ 30ga short needles (width of a human hair). Don’t even feel it. I’ve seen some very serious reactions to those old mega-needles, and won’t go near them.