Maus bocados literally translates to "bad mouthfuls" or "bad bites," but it's an idiomatic expression in Portuguese meaning "bad times" or "rough patches."
In the song, the singer uses this phrase to describe the difficult emotional period he and his ex-partner are going through after their breakup. He sings, "Eu também passei por esses maus bocados," meaning "I also went through these bad times," highlighting a shared experience of suffering and longing.
A friend has told the singer that his ex still thinks about him — "Sei que seu coração falou de mim" ("I know your heart spoke of me") — and that a certain song on the radio brought the sadness right back to her. He admits he's been just as wrecked: "Sofri, chorei, largado" ("I suffered, I cried, abandoned"). He's called her drunk in the middle of the night the same way she's calling him now, "ligando a cobrar" ("calling collect"), both of them "chorando, querendo me amar" ("crying, wanting to love me").
It's a classic sertanejo breakup confession — nobody in this song has moved on, they've just been too proud to say so until the DJ played the wrong track at the wrong moment.