Q. Regarding the prohibition of relating sad news on Shabbos - may one relate sad news to his friend, in order to relieve himself of the tremendous emotional tension of holding it in, or in order to ask his close friend for an eitza regarding the situation (such as one who urgently needs a new apartment as he is being evicted, and he wants to ask his friend for an eitza?)
A. Mishna Berura (307: 3) rules that on Shabbos it is prohibited to tell something that will cause pain and suffering. This prohibition applies also to reading sad articles or detrimental news including posted funeral notices that can depress and bring sorrow to the reader. (Ketzos Hashulchan 107" 43, Menucho Shleimo 8:7, Mishnas Yosef 7: 72, Piskei Teshuvos 307: n. 217).
Horav Shlomo Miller's Shlit'a opinion is that it is permitted in need. Although the friend may become distressed when hearing the doleful situation of his companion, knowing that just by listening and letting the suffering one vent his emotions will bring relief to him, the greatness of this mitzva will also bring a degree of valuable joy to the listener. So much more if he can actually help and give counsel to a friend in need.
Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit'a