Umbral means “threshold” or “limit,” and it is an evocative word that can describe the point at which something becomes too much to bear. In the song, “el umbral del dolor psicológico” refers to the singer’s unusually low tolerance for emotional pain, contrasting with how her body barely registers physical scratches.
Belén Aguilera looks at an old version of herself and doesn't recognise her: "Oficialmente no soy la misma de ayer" (Officially I'm not the same as yesterday). She tried so hard to imitate someone else that "Era mi cuerpo gritando 'Sálvame'" (It was my body screaming 'Save me'), and the change cost her, though "No fue en vano que cambié" (It was not in vain that I changed).
The second verse turns to making art. She suspects everyone thinks "es fácil hacer arte" (it's easy to make art), admits "soy bastante complicada" (I'm quite complicated), and ends on an offer instead of an answer: "Pero yo te escucho si quieres hablar" (But I'll listen to you if you want to talk).