Wearing headphone is not bad; but wearing it for more than 30
minutes at a go is bad for the ears.
When you put on headphones, you cover your ears from the
natural air, which increases production of bacteria by 700% in 1hr. Your ear
drum naturally can not bear influx of bacteria in that quantity so it starts to
react by paining or hearing loss in long term.
Secondly, when you are listening to fast music/ high beat
sound which goes direct to your brain due to headphones, it affects the fine
tissue/membrane of the brain eventually listener becomes hyper or excited which
is bad in long run.