Hi,thanks for query.Once appendix
is removed ,obviously this can not happen again.the pain could as per you guess might be of renal or ureter
stone.At times adhesion(the intestine get stuck to each other) in that area can also lead to this.If she is comfortable then you can wait,if the pain is severe and not responding to conventional analgesic
that you have you need to take her to ER for pain relief.Ultrasound
is required to have final diagnosis.
wishing her good health.