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Ultrasound can push vaccines into the body without needles
(www.newscientist.com)
This is a most excellent place for technology news and articles.
Also tell the person administering it to do it slowly. In my experience, most of the pain was from them doing it too fast. Something about the fluid stretching the muscle in painful ways before it can spread out, or something.
That tracks with my experience. I'm shot-tolerant, so I have the calmness to observe. Of course, some are also just inherently more irritating/painful than others, and there's different volumes of liquid as well.
For instance, if you're shot-averse, get Pfizer Covid rather than Moderna Covid. It's ⅓ of the size/dose.