plumber or contractor?

[birdmove]

I have a leak in the tub/shower in my main bathroom. Not standing water on the floor, but the drywall shows signs of a leak. Areas that look like bubbles in the drywall around the shower surround. Looks like for access, either the whole shower/tub assembly would have to come out, or the drywall in a closet. If that drywall was cut away from inside that closet, the source of the leak. Should I contact a contractor, since drywall work will have to be done, or a plumber? Don't think a plumber would do drywall.
Any suggestions on who I could contact for an estimate? Thanks for any comments and suggestions.

Jon in Keaau/HPP