Because of lack of training and gradual built up, those sudden bouts if running must have lead to loading of the tendons. Rest for few days then gradually start building up with proper running shoes. Meanwhile apply ice to reduce pain.
Next Steps
If the pain still persists after few days of rest and icing then see a sports physiotherapist, if in Mumbai find Flex Physiotherapy Centre, Malabar Hill
Health Tips
Do not stretch the calf till you are advised by your physio.