Kidney stones my 19 year old daughter has had many kidney infections this past year. I took her to the ER last month and they gave her antibiotics to take, she finished the bottle but was still having pain in her left kidney. We went to her regular doctor

Recurring UTI. I would recommend should be evaluated by a urologist. Recurring pyelonephritis (infection of the kidney itself) is a serious issue in a 19-year-old. It should be worked up with x-rays and other testing. There are congenital abnormalities that need to be ruled out.
Your. Your daughter might need to be reevaluated by her physician. The l kidney pain is concerning, especially in light of your son's history of having multiple kidney stones. Often kidney stones are found in family groups. She may need an xray, ultrasound or ct scan of her kidneys to see if she has kidney stones. Best wishes.