To Caroline Polachek, a “pang” is an adrenaline hit or a nostalgic gut-punch. Her brilliant solo debut fully embodies the term, wedding composerly elegance and Auto-Tuned artifice to stunningly physical effect. The title track climaxes in a gasp that seems to burst from between the listener’s ribs; “I Give Up” slumps like Polachek crumpling to the floor. Pang is as novel (the dazzling Escher-staircase-like “New Normal”) as it is fluent in pop history: “Look at Me Now” recalls Britney’s “Lucky,” “Caroline Shut Up” subverts girl-group pouting, and “So Hot You’re Hurting My Feelings” evokes Polachek’s alma mater Chairlift.