hi.. as your doctor rightly said, it could be a renal/ureteric colic... Get one ultrasound
examination done in order to see if there are any more renal stones
.. if it is there, it needs to be treated based on the stone size.. see your urologist
if stones are found in the kidney
.. if it is not there, drink lots of water, aviod alcohol/smoking/aerated cool drinks.. stop palak/spinach, reduce intake of tomato.. do regular exercise, but dont dehydrate yourself.. all the very best..