Haven't heard of misphonia before and I haven't heard of anyone experiencing it.

The closest to this is my sensitivity to loud noises in general, like loud music in a club or a bar. If I'm too long in an environment with intense noise my heart starts to beat and my breathing accelerates. It's like getting overstimulated or "overcharged". But luckily there are earplugs which I always take with me when I'm anticipating of going out (those rare occasions, like celebrating someone's graduation or birthday). And the experience is so much better.

This is because I recognize myself as highly sensitive person which is a concept of describing people with more sensitive nervous system and attributes correlated with it (like sensitivity to intense external stimulus). The concept isn't pulled out of nothing but has a strong science behind it (read the book of Elaine Aron, the inventor of the concept, where he described the science behind it).

On it's core it's a neutral quality which can be thought as a part of neurodiversity in the human genome. It might have negative implications because "highly sensitive" can be associated with being emotionally unstable (not denying a highly sensitive person couldn't be unstable, but having the attribute doesn't cause it).

But in my daily life I don't really think about it anymore and I don't really "label" myself with it (except now, hehe). But it sure was a good tool to understand myself better and it has definitely increased my self-confidence.

Got little extensive with my answer but you know, can't help it when I get into something interesting :D