The speaker feels small and hemmed in. Calling themselves "finite as my picture frame" suggests a life reduced to a single portrait: limited, fixed, and already sitting still on a wall. The line about being "full of shadows" adds a sense of gloom, as if something dark has settled inside that frame.
Then the poem turns restless. The speaker "breaks" their neck looking over a shoulder, which suggests a nervous, almost painful need to check what is behind them. It could be fear, regret, or simply the habit of watching for danger. The final lines widen out to a bewildered question: how did everyone end up in a "new rogue world"? The word "rogue" makes that world feel unpredictable and out of control.
The title, "Citizen X," points to an anonymous everyman, so the speaker's unease seems meant to be shared. The mood is anxious, disoriented, and quietly lonely, like waking up somewhere unfamiliar with no explanation.