Thousands of dissections happen in cath labs all over the world every day very rarely it is painful . The answer is not clear. Both have rich vasa nervorum. Aortic dissection involves media and smooth muscle . Coronary dissection may also be a equally painful , probably we are not recognising it ! or we attribute all chest pain in ACS to ischemia .
Deep dissections into the smooth muscle should be painful. Type c nerve fibers carry pain signals from heart