These elements in the story, in my view, probably don’t actually have any special symbolism attached to them. They are, rather, mainly a sort of background “noise” that forms part of the ambience of Yevgeny Petrovich’s home. One almost gets the impression there is something soothing and annoying about them at the same time.
The rather unusual situation of having to confront his very young son Seriozha about smoking is at the heart of the story. Yevgeny Petrovich finds that he can get his point across better by inventing a brief tale than by simply stating the standard anti-smoking message (in its nineteenth-century version—that smoking can cause consumption) prosaically. Do the sounds from above have any effect on him as he’s doing this? Probably not. After his lecture is over he observes that one of the activities from above has stopped, but the other one hasn’t. In other words, “life goes on.”
One person pacing (as if worried or having a toothache) and others practicing scales on the piano are meaningless in Yevgeny Petrovich’s world. Like other naturalistic writers, Chekhov places little details in his stories almost because they have no individual significance, among the mass of detail that surrounds us. One could possibly make a case that both the piano-practicing and the man’s pacing are a reflection of Yevgeny’s own problems, but this might be a case of reading a superfluous message into a straightforward story that works very well on a basic level, without our adding complications to it.