I've never been to a doctor to know for sure if I have any hearing loss or not, but I imagine I probably do. I have to ask people to repeat themselves a lot, and I doubt it's always them. (Of course, I always blame it on them, ha ha!) If I do have some true hearing loss, I imagine it's from listening to my headphones too loud.
That is super easy to do, especially if the headphones aren't good at blocking out ambient noise. Then you keep turning them up to hear the music and blast your ears without realizing it.