Manny Pacquiao -- I'M RETIRING ... From Singing

Big announcement from Manny Pacquiao -- the boxing champ says his singing career is OVER ... telling us, "I love music, but I don't think music loves me."

Manny appeared on "TMZ Hollywood Sports" on Reelz (Mon-Fri 6PM ET, 3PM PT) and broke heartbreaking news ... telling us there won't be a follow-up to his two wildly successful albums.

"I stopped singing," Manny says ... "I like singing. I love music ... but I don't think music loves me."

Manny -- who's promoting his new documentary "Manny" -- says he's still very proud of his musical accomplishments ... saying, "My first album was platinum in the Philippines, so that's good enough."

Hopefully, he'll change his mind ...