Italian-American slang for heartburn but it can also mean mental aggravation.
The word is Italian-American slang derived from the Italian "agitare" meaning "to agitate.
Found an article about one of the stars of The Sopranos who's working on a new movie about feuding pizza parlor owners. The title: "Agida." ...
"Eew, I've got agida." (swallows) "Give some soda now, YUCK!"
A burp accompanied by a small amount of the contents of one's stomach that does not ascend past the lower esophagus. A "pukey burp".
Don't hug me so tight...I just had agida.