It seems like nobody really knows SPD exists, apart from those who have it, and those who diagnose it. Even this subreddit is quite low-traffic.
My mother still can't wrap her head around it. I explained the whole thing a number of times, but it's all "so you don't like velvet?" Bleah.
We all have annoyances, sure, but SPD is where everyone except you can tune out the shirt tag stabbing your neck, or a random beep-ding-beeping OMG TURN THAT BEEP OFF!!! Your brain prioritizes the annoyance as the most important thing in the world.
It's also a lifelong thing (yay) -- sensitivities show up as a tiny kid, though specifics may change. It usually involves all 5 senses, and aren't from trauma, like hating a food because you once had a stomach flu and puked it up.
There is treatment, occupational therapy, as well as avoidance (earplugs, clothing that's tolerable, etc.) and "antidotes." For me, soft squishy plastic tubes (lotion, toothpaste, etc.) are incredibly helpful. And people are learning, a lot of stores have quiet hours for sensory haters.