Calcino comes from the verb calcinar, which means to calcine, to burn to ashes, or to reduce to powder by heat. It's a strong and evocative word that isn't commonly found in everyday conversation or many songs.
In "Cómo Duele," Luis Miguel uses me calcino de pensarlo to express an intense, almost agonizing jealousy and pain at the thought of someone else having been with his beloved. It conveys a feeling of being consumed by this thought, burning up from the inside out.
“Cómo Duele” is Luis Miguel’s heartfelt confession of remorse, jealousy, and redemption. The singer looks back on youthful romances where he may have played carelessly with someone’s feelings, admitting that he is now “paying the debt” with every tender kiss he gives his current partner. Behind the silky vocals lies a man who feels the weight of his past mistakes yet hopes that loving the right person, right now, will balance the emotional ledger.
The pain, however, runs deeper than guilt. Luis Miguel grapples with a sharp jealousy over the memories his lover carries from before they met. It hurts that someone else once showed her the moon and gave her that first shiver of love. He imagines those earlier kisses and practically “burns” at the thought, wondering if he will ever overcome it. In short, the song captures the bittersweet blend of trying to make amends for yesterday while wrestling with the ghosts of a partner’s yesterdays—a universal sting that truly explains cómo duele (how it hurts).