Is there a map of 14th century London markets? Where did apothecaries do business?

London was constantly changing during those times, so it's unlikely that there are any surviving maps that might depict a street grid from those days. As wells dried up, new ones had to be dug and new channels were constantly being constructed to take the place of the old ones. Additions to fortifications and to the dock-works changed the face of the city, though some of the major thoroughfares survived the many changes the city went through. I'm not aware of apothecaries having any particular location within a marketplace, though they might have been situated in a specific part, you'd likely have to speak with someone who's knowledgeable about Medieval London if you want details on something like that.