Any explanations for rapid onset of pain under sternum followed by laboured breathing?

Pinched back muscles often send pains around your body on the nerves to be pains in the rib, chest or heart areas. When the back muscles tighten up they can pull the muscles going around your ribs tight as well so they can't expand to get a good breath in. Freeing up your back muscles will get rid of these problems for you and here's how to free them up: