32 year sufferer, back behind the microphone

32 year sufferer, back behind the microphone I've had a stutter since I was 8 years old. it seems to run in the family, my grandad had one, his grandad had one. I was the first to have one in a generation that you had to go to university and make something of yourself. In fact I was the first in my family who went to university. While I was there I met people who didn't care about my speech and we connected with music. We made a band and did some shows. My condition never affected me while singing, I didn't know why or how but as long as my luck carried on I would too. Has there been any reason found why this happens? I can sing a full 45 minute set, and speak in between songs. But as soon as I come off stage I can't.