I have been getting severe sour stomach, diarrhea and vomiting on a fairly frequent basis. what could this possibly be from?

Diarrhea: Most diarrhea of sudden onset are viral. They go away on their own and just keep up with fluid. If it persists for several days or if it occurs in groups exposed to the same thing, consider infectious process such as e. Coli. That has to be treated with antibiotics. Consult your physician and you will be given the proper work up, treatment or advise. Symptomatic treatment may be needed.