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If the poop is sour that means it is acidic and it is because of acidity and indigestion
.You may be suffering form acute gastritis
or GERD (gastro esophageal reflux syndrome).Consult a doctor and he will prescribe you an anti-emetic along with an antacid
and you should be fine in a day .Also please take care and don't have spicy food;heavy meals;fatty fried food as it will increase the acidityand the poop may come again.