My heart hurts steadily but more when i breathe. is this lethal?

See doctor today: Most commonly this is an inflamed or bruised muscle or bone in the chest wall. Other causes, especially because its positional, include inflammation of the heart sack, the lung, or the internal organs, like the pancreas, stomach, gall bladder, or esophagous, rare, but dangerous conditions include a pulmonary embolus (blood clot in the lungs) and heart attack. Ocp's and smoking increase risk.