www.tillys.com usually has a good selection.
PacSun has gotten too kardashian/jenner for my taste.
My O'Neill and Fox boardshorts are tried and true... but surprisingly I found a pretty legit pair the other day at Lulu Lemon. Yeah yeah I know, but they have one specific pair of shorts I like to run and work out in and got suckered in this time because Ive had the hardest time finding shorts and bathing suits this season.. but these had a cool print and were reversible.