Not a uniquely Japanese thing. I remember stories of my elementary school being haunted, and that the reasons the showers were blocked off was because some kid got bullied so bad she drowned herself in the shower.

Kids will just make up scary stories, then a gullible one will believe it's real, cite evidence that's them being paranoid, and then it gets immortalized after a while.

There's admittedly more literal magic and stuff here than there was back home, but I'd say most of these are still more story than ghost if you catch my meaning.