I went to the local pharmacy to buy cold medicine.
Refers to the person who runs or works in a pharmacy. Often used in a traditional or informal context; 薬剤師 (やくざいし) is the formal term for a licensed pharmacist.
The owner of that pharmacy is very kind.
Compound of 薬 (くすり, 'medicine') and 屋 (や, 'shop' or 'dealer').