Why do I stutter? Could it be from deep buried trauma?

Why do I stutter? Could it be from deep buried trauma? Hey guys I need advice cause I am struggling with this for a long time and don't know know! So anytime I talk about certain parts of my past I end up stuttering, panicking and crying and not able to stop for hrs. Like I want to talk about it like to my partner I trust her but when I try and talk about it I just break down, stutter and panic alot. I have just also today tried to talk to my occupational therapy support worker and its the same it's like my body shuts down completely and goes on red alert. He asked me why this happens and I couldn't tell him which then really annoyed me I hate stutter. My partner seems to think there is like a deeper reason like deep buried trauma, I have never proceed ever and buried it and forgot about it and my body goes in complete panic mode when I try and talk about one thing I want could that be a reason? Could there be something linking to that and my my body refuses to remember that trauma or relive it and shutdown? I hate it, it's honestly hell like it's a couple of things that I can't talk about and I don't know why, I was diagnosed with adhd last year and found out I have bpd and c-ptsd was diagnosed with both of them 15 years ago but no one told me. I didn't have the best childhood I was forced to bring myself up at the age of 5 and was abuse, neglected ect I can't remember alot of my childhood other than being alone all the time. One part I do remember is being locked in the house for days whilst my mum sold her body and I would be alone with no one. Then when I try to talk about after that I just break down, stutter and panic. My partner says it's like a fear panic like my eyes look petrified. Any advice would be appreciated cause I hate not know why.