Visceral pain can cause referred pain, such as shoulder pain from diaphragmatic irritation or arm pain from a heart attack, due to viscero-somatic convergence.

“interesting characteristics with visceral pain is there's something called viscosmatic convergence meaning that the afference the information coming in from the gut from the uh thorax converge with the same sensory systems from the rest of our different parts of our body. So um you know you may remember the old medical school adage uh C345 keeps the diaphragm alive. Okay we all we all had these in in med school. Well that means that the third fourth and fifth cervical nerve roots subserve our diaphragm which help us breathe. When the general surgeons or others are operating and they get blood under the diaphragm it irritates the diaphragm. And what patients will typically complain of shoulder pain because the shoulder is subserved by the fourth and fifth cervical areas. And so when they had shoulder pain, the answer wasn't, you know, something's wrong with their shoulder. It's they had some irritation of blood under there. It's why when people have a heart attack, pain radiates out into the arm because you've got the upper thoracic nerves subserving the heart that overlap with the nerves that go down your arm and the nervous system gets confused and that's how it's expressed.”