Pichar is a very common Puerto Rican slang word that means 'to ignore' or 'to brush someone off'. It's an essential piece of Caribbean Spanish vocabulary and a great word to know if you love Bad Bunny's music.
Interestingly, it's derived from the English verb 'to pitch' (like in baseball), but the meaning has evolved completely! In the song, he sings "Toca seguir, pichar y olvidar" (It's time to move on, ignore, and forget), showing his resolve to leave the past behind.
Bad Bunny hits us with a breakup track that trades big dramatic tears for petty honesty and local Puerto Rican humor. Even though it is always warm back home, he starts off sitting by the river at 6 PM feeling freezing cold: "Y aunque en PR todo el tiempo es verano, estoy pasando frío escuchando estas canciones" [And even though it's always summer in Puerto Rico, I'm freezing listening to these songs]. He wonders which of them will suffer more, bluntly admits "ojalá que seas tú" [I hope it's you], and decides he is done competing for someone who looks good but tells lies.
The real punchline is the title itself. A boquete is a pothole, and Bad Bunny tells his ex: "Tú eres un boquete en PR, por eso es que te esquivo" [You're a pothole in Puerto Rico, that's why I dodge you]. He also drops a funny geographic burn about a trip that fell apart way too early: "Te iba a llevar pa' Maya y no llegaste ni a Arecibo" [I was going to take you to Mayagüez and you didn't even make it to Arecibo]. By the end, he reminds himself that he has fallen in love 516 times before, so he will just pichar (ignore it / brush it off) and move on to the next one.