I am a foreigner working at a company in Japan. My native language is English but I believe I can converse somewhat moderately well in Japanese. After dinner one evening, I heard the following exchange between two of my coworkers, who are Japanese natives (this may be not the exact wording, but this is the best I can recall):
On another occasion, I have also had the following exchange with a different Japanese friend who does not work at the same company (again, the wording may not be exact):
As someone who was raised in another country primarily speaking English, I can not once recall ever thinking, "Gee, my intestines hurt." So my question is, under what circumstances would a Japanese person think specifically that their intestines hurt as opposed to their stomach? Or does 腸 include some other part of the body in the abdomen where you would feel pain?
I suppose I could understand if the person were suffering from constipation or diarrhoea for example, but I've never personally regarded either as a "pain in my intestines", nor have I ever recalled experiencing any kind of sensation that I could pinpoint as coming from my intestines, so the idea that "自分の腸が痛い" seems unusually specific to me.
Is this some kind of cultural difference, or am I just weird, born without feeling in my intestines or something?
I realize now that I don't recall actually hearing the specific expression "腸が痛い", so I believe my original premise may be flawed. As naruto's answer suggested, both cases were most likely a case of informal "diagnosis", which I admit seems obvious to me now in retrospect.