Yes, it is possible for adults to develop reflux - although it is less often than in children. If this is a concern, an intravenous pyelogram can be considered to evaluate for renal scars. An ultrasound can also be considered to look for anatomical abnormalities.
If there is concern about kidney stones, the most sensitive test would be a non-contrast spiral CT scan.
These options can be discussed with a urology consult.
Followup with your personal physician is essential.
This answer is not intended as and does not substitute for medical advice - the information presented is for patient education only. Please see your personal physician for further evaluation of your individual case.