Chanca piedra is a mild baseline drug known as Bhumyallaki in Ayurveda. If you have bigger size stones only Chanca will not be enough.
In Ayurveda there are many good formulations like varunadi kvatha, chandraprabha vati, gokshuradi guggulu which can help in breaking the stones and preventing their recurrence. So take proper consultation before starting medicines.
Next Steps
In the mean time start taking cystone tab of Himalaya pharmacy 1 tab three a day as a temporary solution.
Health Tips
Avoid eating spinach, potatoes,milk products etc