I wonder where my stutter came from and why he got worst

I wonder where my stutter came from and why he got worst Recently I wonder where my stutter came from? A little background about myself I’m 24, now at college, i stutters from always and that always been difficult. That stopped me a lot in my life and ofc still that really hard. Actually I’m a seller so my job is to talk with peoples and also I’ve been a combat solider for a while. In the last year my stutter got worst, and I wonder why I even stutter? None found the real reason, that a physical problem?mental? The worst thing happened to me(according to the therapist) that my parents discovered when I was young but actually I don’t care front that haha I don’t have problem with confidence, I’m a party promoter and been with girls and also i have gf and had few relationships in the past and the stutter didn’t interrupt so I really think the problem no from confidence or nervousness I will be glad to hear what u think