Looking for a nice beach and a cool town

My husband and I are looking for a nice beach and a cool town that has live music. We are travelling the last 2 weeks in March. Any ideas?
Thanks

By "Live Music" I assume you mean doing Massive quantities of drugs and listening to the music in your head--You can do that anywhere. Not sure if there is any place in Central America with Music--don't recall ever hearing any.

In Panama, about the only beach town with live music will be Bocas Del Toro -- but it will be salsa/meringue, and pretty funky. On some holiday weekends, you may find bar bands in Coronado and Decameron. Web search them, and you can find hotels.