why do you have army green poop for a week at a time with stomach pain?

There are a lot of reasons but a common one is that you're seeing bile. If it goes through fast it tends to stay green.

It can also be from some diet supplements, especially ones rich in iron.

Another possibility is salmonella poisoning. Do you have diarrhea, fever, and cramps? Since you said it lasted a week that is a possibility. You may want to check with your doctor.

Hope it helps.