i have lived in both.
just live your life normally, you will meet a girl naturally and very easily.
Just eating at the night market you will see plenty of girls, just smile and say hi.
its very, easy.
if you want some fun, then fur sure, Pattaya is the place to go, although fun girls are available in Hua HIn also.
Just go to the massage places, you will get fun in the majority of them