Pichaera is a colloquial term, particularly used in some Latin American countries, that refers to a state of indifference or not caring about something or someone.
In the song, the line "Mera, yo estaba activo con la pichaera" implies that the singer was actively trying to be indifferent or not show interest. It's an interesting word choice because it's not a standard dictionary term, adding a layer of street slang and authenticity to the lyrics.
Ever wonder what's going on with your ex? Andy Rivera and Feid totally get it in "Qué Le Pasa A Mi Ex [Remix]"! This song is all about that confusing situation where an ex claims to be over you, but their actions (and even their voicemails!) say otherwise.
The guys sing about hearing their ex is still thinking about them, even though she's supposedly moving on. They're like, "¿Qué le pasa a mi ex?" [What's wrong with my ex?] because she's out partying, trying to get their attention, and still talking about them. It's a playful look at that push-and-pull of an ex who "me odia y me quiere" [hates me and loves me], and how sometimes, despite their best efforts, they just can't quite let go. They even joke that she's "pasaste de moda como el Atari" [out of style like the Atari] – a pretty blunt way to say they've moved on!