My mum does the same thing. If I complain about anything she'll make it al about her. Yes, she did have a sh*tty childhood etc but that doesn't make my problems any less real. I'm not really sure how you can get through to people like that. Instead of volunteering could you maybe get a hobby and meet people that way?
My mom had a crappy childhood too. She doesn't get it how I feel when I see both of my younger siblings that are in a relationship and living on their own then seeing her and my dad being married over 30yrs. and them going out with their friends and chatting on the phone. I don't get it when my mom tells me I don't need friends when she has friends of her own.
I realized that the fact of not having friends didn't bother me until my late 20's when I started hanging out with an old friend that doesn't have anything to do with me anymore and opening a facebook account. All facebook did was intensify the fact that I don't have any close friends, just merely acquaitances or former co-workers. I wasn't really into myspace
Prior to that, I was in my own little world, never got into the "party" scence like my siblings did because my mom was obsessed about us not becoming alcoholics, heck, I barely touched any beer until I was after 26yrs.