ch4509 :
Is it from sound, fit, or some other reasons?
Both.
Fit, well that's obvious, I say fitting earbuds is even more finicky that shoes fitting. IMO, anything plastic, hard that comes into contact with your ears and relied upon to keep some kind of seal (pressure) will eventually bother you, if not right away. These days I use a pair of etymotic IEM with medium-hard 2-flange buds to make the seal and I can wear them for hours. Not everybody like the feel of IEM but if you are able to, to me that's best thing next to custom-made ears molds. Buds with a loop around your ears, looks futuristic cool but Gosh I'd stay away from them.
Sound, I have auditioned phones that everybody say is great but I can't stand some frequency that it...