"Under Control (Extended Mix)" by Calvin Harris & Alesso (ft. Hurts) appears to be a song about a complicated love relationship and the struggles one faces when trying to let go of someone they deeply care about.

In the verses, the singer expresses the feeling of being anyone, a fool in the sun, possibly describing how insignificant and vulnerable they feel in the presence of the person they love. The line "Your heartbeat of solid gold" could symbolize the other person's unwavering love and loyalty. However, the singer acknowledges that their love is unrequited, admitting, "I love you, you'll never know." The line "When the daylight comes, you feel so cold, you know" suggests that despite the warmth of their affection, the other person remains distant and emotionally unavailable. The singer confesses their fear of letting go of this unrequited love because their heart is too deeply invested.

The chorus emphasizes the longing for a change in the relationship. The line "Waiting for the fire to light" indicates a desire for passion and excitement, hoping that things will improve between them. The lyrics "Feeling like we could do right" suggest a belief that they can overcome their difficulties and make things work. The singer wants to be the one who brings a positive change to their situation because "freedom is a lonely road." This line implies that the singer feels trapped in this unrequited love and longs for the freedom to move on.

The drops and instrumental build-ups in the song represent moments of heightened emotion and an escape from the complexities of the relationship. They serve as an opportunity for the listener to immerse themselves in the music and momentarily forget their troubles.

Overall, "Under Control" portrays the conflicting emotions and struggles one experiences in a complicated love relationship. It explores themes of unrequited love, longing for change, and the fear of letting go.