Does one have to stand during kriyas hatorah? There are some portions that many people stand for, is that an obligation, or a nice thing to do?
Does the halacha of not having your back to the Torah only apply to people close to it, or to everyone in shul?
The issue of standing during Kriyas Ha-Torah is a matter of dispute between Shulchan Aruch (146:4) and Rema, the former writing that one sits, and the latter that some are stringent to stand. The Mishnah Berurah writes that standing is a worthy practice, although the Vilna Gaon favors the custom of sitting, as does the Arizal (cited in Kaf Hachayim).
Concerning standing in various places, the Rambam was concerned about people standing for the Aseres Ha-Dibros, and contemporary poskim also express a concern that people will think that not all parts of the Torah are equal (see Iggros Moshe, Orach Chaim 4:22; Tzitz Eliezer 14:1; Yecheveh Daas 6:8; the concern is based on the Gemara, Berachos 12). However, other poskim are not concerned for this, and the common custom remains to stand in various places (Devar Shmuel 276; Mateh Yehudah 1:6; Beis Yaakov 125).