It all started in an accident when I ran into someone and hit my chin really hard, and when I got up I had a pain in the bone onto my right ear, and since then whenever I put on headphones, I can't hear the backside of the music, and it feels like my hearing depth is distorted

I forgot, to say, the pain has subsided. And it feels like I can't hear the right-back side of the ear buds that I have. Everyone of them

There could have been some trauma there. I would go get it checked out. Could have caused swelling around that area, wich would explain the muffling I think. I could say for sure. This is serious though. I would get it checked out.