I asked your father if when praying by hassidim, who as a rule do not say tachanun, if I should say tachanun on my own. He said no.
But, AA seems to have offered an alternate psak. Please see this post:
Author: Mitnaged Man
Date: 12/25/2003 12:43:00 PM
1) Please clarify as I must have misunderstood what the proper course of action is. Is it yes or no ?
2) If yes, when should i be said ? Please keep in mind, after the shatz is done repeating the amida, he says kaddish and then all say alenu. (Mincha)
3) If no, please help us understand why not ? Is it because kaddish is a hefsek and it breaks the tie between tachanun and the amida ? Or is it because we may rely in this case on the opinion that tachanun is only a reshut and not a chova.
Thank you in advance.