Everyone is different. I've had the pneumothorax-and the surgery-Of a small pneumo-the pain will increase as you bend forward over the handlebars-if that is any help. They also show up on x-ray. But does it Hurt to breathe? Then I'd say you'd pulled a muscle in your chest wall. With a pneumo-it doesn't just hurt to breathe-the pain can be quite dull-but I assure you-it can be significant. It is more that you cannot get your breath. None the less-chest pain-should be investigated-to rule out the differences between muscle spasms and something going on cardiac wise.