Well, without knowing the relevant clinical details or a detailed clinical evaluation it would be difficult to comment specifically on the situation. Possibilities that may need to be considered include residual stones, trauma/ injuries, inflammation etc. If the pain is mild-moderate, I would suggest taking plenty of fluids and pain killers suggested by the doctor. If severe, I would advise visiting the ER. A review by a urologist may be sought at a later date.
Hope this is helpful.