Hi welcome to the health care magic Left sided abdomen pain can be from stomach flu... Stomach infection like gastroenteritis can lead pain in back also as referred pain... For your condition you can be prescribed rabeprazole like antacid drug As pain severe and if fever present broad spectrum antibiotic like ofloxacin and ornidazole combination prescribed Avoid outside fried food and non veg foods for few days Fruit juice and semisolid diet preferred If pain severe enough then better to investigate with USG abdomen also for further work up Take care Hope your concern solved Consult physician for examination with keeping all this in mind