There in no shortage of pharmacies in India. Be aware that many are Ayurvedic pharmacies and don’t sell real medicine. Pharmacy can be a closed space with white walls and neon banner advertising some cosmetic product but more often it will look like this- unattractive open space with a sign:
The pharmacist might not wear white but don’t worry, he is a professional. Most of the medicine is treated like OTC medicine. Antibiotics, analgesics and other medicine that needs prescription in the west doesn’t need the prescription in India.
When buying medicine you might get just a blister filled with pills, not the whole package. Don’t count on getting usage instructions as well. The pharmacist will explain how to use the medicine.
If you want to avoid getting sick than check out the hygiene things and drinking water issues.