Since how long are your symptoms?
Do you have bloating, diarrhea/constipation?
Any significant past medical or surgical history?
What is the maximal pain site on the abdomen?
Any specific area of tenderness?
Following would be the possible causes;
1) Gall stones or gall bladder disease; if not removed already
2) Peptic ulcer disease
3) Mild pancreatitis
A severe pain always warrant a medical examination and investigations like ultrasound and CT scan with liver function tests, pancreas function tests and endoscopy (camera exam). You can try antacids like Maalox or Tums with acid blocker Prilosec. Dramamine for vomiting can be taken. All of them are over the counter medications.
Please feel free for your follow up questions.
You are most welcome.
Kidney stones do cause vomiting, but nausea and bilious vomiting is usually not common. A first time kidney stone in your age group is almost rare, so I did not mention it. Lower left back side pain is caused by ureter (tube which joins bladder and kidney) stone, but again they are rare cause in your age group, if there is no history of previous stones and they would usually have urinary symptoms and pain radiation to thigh and labia. Diverticulosis and diverticulitis can be the other possibility.
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