What does it mean if someone is suffering with chest cramps/pain? hurts when he breathes.

Pleuritic chest pain: Is painful chest with breathing and may be from a variety of causes from less serious such as muscle related (e.g. costochondritis) to more serious such as pneumonia (infection), pericarditis (heart inflammation) or pulmonary embolism(clot). So needs doctor assessment and urgently if breathing difficulties as may need tests run to sort it out.