Why does my mother hurt me so much!!?

Im 37 yrs old and I have 2 brothers. I am the middle child and for yrs my mother has treated me unfairly on everything. she plays favortism with my kids and my youngest brothers kids. Im over it, but when my dad died yrs ago my brothers were left everything to him. i never mentioned this at all, but i wonder why she treats me this way??? I have confronted her on her favortism and i only get the hang up. she never wants to talk to me about how i feel, and i really would love to shut her out for good and the rest of the family. she has only caused me so much grief in my life and my family....i just wish there was another alternative. but its sad that i have never had a tru mom in my life and i have a daughter whos almost 20 and i am thankful for our relationship. it was tough for me because i never had a mom to be there for me for anything. i was wondering is there anyone out there dealing with the same situation. my sister in laws get the best treatment from her, and mom gives the best gifts to them. its ridicilous. HELP!!