Boteco is a very Brazilian Portuguese word for a casual, often small and unpretentious bar, similar to a dive bar or a local pub.
In the song, the singer is
"É Problema" is about the loop of heartbreak. The singer is at his usual bar, staring at the same table and the same beer, but his hand tells the real story: there is no ring on it anymore.
He lays out the logic almost like a proverb. Whoever misses someone suffers. Whoever suffers gets thirsty. Whoever is thirsty drinks. And whoever drinks starts remembering all over again. Drinking to forget the breakup just brings the memories back, so one problem drags the next one behind it.
By the end he admits it plainly: he is stuck in a cycle that is honestly a little sad, going in circles instead of moving on.