I started noticing mine after I recovered from COVID. I think it's somehow related to either COVID, my autoimmune response to COVID, or the medications I took during it. I'm going on 1 year and zero things affect it from what I can tell. Never was worried about a serious disease. But it has changed my life a lot. I am a 24/7 twitcher. I haven't gone longer than about 30 seconds without my muscles contracting in the past year. I normally feel it about every 1-2 seconds. It's relentless and brutal. I've tried everything everyone has suggested. Seen all the docs and tried all their suggestions so far. Nothing changes it for better or for worse. Seems to be a permanent chemical/DNA change type of thing that science doesn't understand yet. And unfortunately, has no interest in understanding.