Stammering and selective mutism.

Stammering and selective mutism. Is there any relation between stammering and selective mutism ? I have selective mutism more than stammering. When someone ask my name or in my introduction i get completely struck. Sometimes I want to say something to someone but my words don't come out of my mouth and I feel frustrated and hopeless. I have done speech therapy but still there's no improvement. Wish I could die in peace and never face such situations again in my life.