May one be involved in excessive “tircha” on shabbat that is neither a melacha nor muktzeh, although not for mitzvah sake; i.e. rearranging furniture?
Answer:
It is forbidden to exert oneself without need on Shabbos (Mishnah Berurah 324:9; Peri Megadim, E.A. 317:9).
Although the prohibitions on Shabbos divide into specific melachos, there is also a general obligation to “rest,” as the Ramban (on the Torah) explains. According to the Ramban, if a person will move furniture around for the whole day, he will violate the positive obligation to rest on Shabbos.
Although there is no prohibition on exertion per se, one must therefore avoid unnecessary exertion, and leave the rearranging of the living room for another day (unless the new arrangement is required for the Shabbos).