Mild, intermittent right-sided abdominal pain that shifts between upper and lower is most commonly caused by gas, acidity, or irritable bowel syndrome. Without fever, vomiting, or constant severe pain, this is unlikely to be something serious like appendicitis or gallstones right now.
Next Steps
Watch for 2-3 more days. If the pain becomes severe, constant, or comes with fever, vomiting, or loss of appetite, get an ultrasound abdomen done immediately. Feel free to consult me directly on Practo for a detailed evaluation.