there is a fic i remember reading from a while ago but all i remember is that the main character died and after going to equstria became twilights "clone" for lack of a better word and i also remember the the song black hole sun by soundgarden shows up once so if anyone knows anything about it that would be great

I know of two possibilities An Unexpected Twilight and We're...Twins...yes...twins... the first one however is listed as cancelled

There are 2 more ones that i can think of right now:
https://www.fimfiction.net/story/340830/double-vision The Character does skydiving but right before the deadly impact he is sent straight to equestria becoming a new twilight lol.
https://www.fimfiction.net/story/283983/twilights-twinlight Character dies on his way to school due to a stupid driver, the Character's name is Ken btw