That's a really good question!
I don't know if I had "super hearing," but I've always been extremely sensitive to sound (especially discordant noise), and kept the volume of everything as low as possible. I'm sensitive to light, as well. I also have a need for larger personal space than most people. In other words, standing in a grocery line can be quite uncomfortable if the person behind me stands too close, that sort of thing. Seems like I read somewhere that about 10% of the population are "over sensitive," and that normal environmental stimuli is too much for them. We are the hermits