I have sour stomach and diarrhea like water for 2 days. what is the cause of this and how can i get rid of it?

Go see your doctor: You might be describing food poisoning, viral gastroenteritis, or even a bacterial infection. Or it maybe that you have a coincidental gastritis (bad heartburn) along w/some nonspecific diarrhea. Other causes of diarrhea include parasites (think drinking contaminated h2o while camping), poor hygiene, colitis (typically painful & bloody), and even food sensitivity such as gluten (celiac disease).