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There are some common causes of such abdomen pain related to food intake.The common ones are gastric ulcer, gastitis, GERD, achlasia, hiatal gernia, reflux esophagitis, gall bladder stones, cholecystitis, gas pains etc.
As per the symptoms the chances of gastroenteritis may be there which may cause such abdomen pain associated with food intake and diarrhea.The gastric or duodenal ulcer may also cause such pain but usually not associated with diarrhea.
The pain due to gastric or duodenal ulcer is treated with antibiotics like amoxycillin,metronidazole, etc and the antacide and proton pump inhibitors.The drinking of fluid, avoiding spicy food and eating more fibres may ease your symptoms.
The gall bladder stones or cholecystitis may also cause such pain in you and should be ruled out as well.The drugs like tylenol will help in controlling the symptoms of pain temporarily.
The antibiotics may be needed to control the infectious cause related to bacteria causing such symptoms.The commonly prescribed antibiotics are ofloxacin, metronidazole, etc.
You should have the relevant investigations done like endoscopy, barium swallow, ct scan abdomen, blood counts, serum lipase after consulting your doctor/gastroenterologist to know the associated abnormality if your symptoms are not controlled.
The drugs like antacids, proton pump inhibitors, antibiotics may be prescribed for some weeks for the gastric ulcer.The other causes are treated accordingly.
The treatment depends on the underlying cause.
Please feel free for your follow up questions.