Pains come & go all over rt uppee and lower quadrant & centre abdomen, dr says its gastritis & now on nexium, can gastritis cause pains In those areas?

Gastritis. Gastritis typically causes discomfort in the upper midabdomen and wouldn't explain right lower abdominal distress. Right upper distress would be unusual. If discomfort keeps recurring in those areas of the abdomen, I would consult a gastroenterologist for diagnosis and treatment.