The phrenic nerve makes the diaphragm move so that the lungs can fill with air and empty. Diaphragmatic paralysis is a condition where this nerve is not working properly and this makes you short of breath. In many instances the cause is never found. It can occur on its own. However the phrenic nerve originates at C4, so there could be a relationship between your foraminal stenosis at C4 and your paralyzed left diaphragm. An MRI of the cervical nerve roots might provide more information.