A 32-year-old male presents with right-sided chest pain on inspiration and breathing difficulty for 5 days — after someone pushed him suddenly in the chest. This 11-page clinical reasoning guide teaches you why a push is biomechanically different from a punch, how that difference shifts the entire differential, and why the most common diagnosis — costochondral sprain — is invisible on X-ray. Covers the 60-second safety check, 7 strategic history questions, systematic examination (inspection through bedside ultrasound), tiered differentials ranked by push mechanism, the ABCDE chest X-ray reading framework, and a push vs punch comparison table. Includes the teaching pearl every GP needs: a normal X-ray does not mean a normal chest.