The Sony MDR-7506 fits almost perfectly on the smallest setting, but something about the sound hurts my ears. Any nice headphone recommendations for small heads?

Hey there, I'm new to the world of nice headphones. I bought these because I heard they were small and I was having a hard time finding nice headphones for my small head. I was previously using Elecder i39s because they fit me perfectly, but I'd always wanted to buy better ones. They finally broke, so I ordered the Sony MDR-7506.

Most of what I'm listening to sounds a little muddy, with the exception of higher pitches, I think. Some random sounds are extremely clear, but maybe too much? I wore them for 20 minutes before I had to take them off because the sound was hurting my ears (it wasn't loud at all). I turned the volume down very low and wore them for another 2 hours, and now both ears feel a little deafened and hurt worse. I'd like to spend around $100, but I'm willing to spend more if necessary for both a good fit and good sound quality. Any help would be appreciated!