Hi My Mother Age 48 Has Been I'll For Past

Hi my mother age 48 has been I'll for past 1 month due to cold fever and tiredness and but since past 6 days shes suffering frm bad stomach pain. Her scan result says everything is normal but after her light dinner she complains of stomach pain.( no specific place but says the who's stomach )
Its unpredictable what can be the reason. Yesterday and the day before she had hands and legs swollen which reduced today morning. What could be the reason pls help. What test should I take for her. Which doctor should I visit.