"Trouble" was the show stopper Elvis sang in the 1958 film King Creole. The movie was set in New Orleans, hence the jazz influence on the song with the loud bawdy trombone tremolo as well as the flair of some vocal fry that Elvis ends some of those lines with. King Creole still holds up well, so check it out when you can. Also check out Elvis in some of the other movies he starred in, like Flaming Star(1960), Wild in the Country (1961), Blue Hawaii (1961), and Viva Las Vegas (1964). PS. That sound you're wondering about is probably a clarinet. There is a clarinet in the song. For some tasty clarinet, check out Artie Shaw "Begin the Beguine" from 1938.
