Reading Mitzvah related matters:
The prohibition against reading laymen documents, is itself only because of “Mimtzo Cheftzecha”, and the prohibition of Mimtzo Cheftzecha does not apply by the matter of a Mitzvah. As matters of heaven which are forbidden to be done on Shabbos are permitted to be spoken of, and no decree was made by heavenly matters that one may come to also permit mundane matters. Thus certainly there is not to be decreed by a Mitzvah matter against permitted matters due to that one may come to read laymen documents, and will transgress the prohibition of Mimtzo Cheftzecha.
Reading the names of the souls by Yizkor: (Similarly that which is accustomed to read the [names of those] souls [which have passed away] from writing is considered like a Mitzvah matter, [as] they vow to charity for the sake of mentioning the deceased. Look in chapter 306 [Halacha 14/15]
It is permitted to read Mitzvah related matters, as such matters were never given the decree of “Mimtzo Cheftzecha”.
May one read the words written on the Peroches; Bimah etc?
May one read the names of the deceased when no charity is being given in connection with it?
May one read names for a Mi Shebeirach for the sick on Shabbos?
 There it discusses when and how giving a donation on Shabbos is permitted.
 Ketzos Hashulchan 107 footnote 40
 As matters of holiness will not come to be confused with business documents. [ibid]
 Ketzos Hashulchan 107 footnote 41
 As charity is donated on behalf of the sick. Furthermore, it is a matter of the body [health] of which it is ruled that even to read letters which their content is questionable is allowed due to it perhaps containing matters of the body. Now, although there Admur concludes one is to only read it in his mind and not verbalize, perhaps that is only because one does not know the letters content. However if one knows its content of bodily matters then it is allowed. In any event reading the name of the sick is certainly no worse than reading the Mi Shebeirach itself which is allowed.