This response is POWERFUL. So many incredible things in here. It is so extremely true that a lot of us think of the body like a machine, and treat it that way, rehab it that way, strengthen it that way... etc. I was once a coach that operated that way, until my entire life fell apart (actually, thank God)! In my experience, the body follows the brain/mind. The body believes the brain/mind. The body reacts to the brain/mind. However, at least in my experience in the fitness/rehab world, there is never a brain/mind component in our work. Never. As an exercise physiologist, we get one psych class in undergrad and one sports psych class in grad school, and then we are off to treat and strengthen our machines! NO! BIG BIG BIG problem here. Glad you see this! One day, and if enough pioneers like Dr. Schubiner, Dr. Sarno, Dr. Clarke, Dr. Hanscom, and many more keep pushing, this will change. This HAS to change. It is bound to change. I hope it changes sooner rather than later.
One thing that has helped me immensely is studying Internal Family Systems by Dr. Richard Schwartz. It has allowed me to develop an entirely new relationship with my psyche, and has also made me look at the protective parts of the mind that send me symptoms, in an entirely new light. Actually, it has been a profound tool in my personal healing journey, as just like you, I have a trauma brain that is often very afraid to accept this condition, particularly when it gets triggered. I should add, I have even been diagnosed by Dr. Schubiner in person! However, in times of fear, my protective parts do what they think they need to do... OUCH.
A quick example of how I used to talk to this part of my mind and symptoms before IFS: "These symptoms are just Mind Body Syndrome! They are harmless, I am not hurting myself, so I am going to deadlift and run up this mountain and screw you brain! How could you do this to me? I will not let you do this! I will not let you stop my recovery! I am doing it my way!"
This Morning Deadlifting: "You are doing this perfectly. I know it is really tough, but just hang in there, do as much as you can do. Back off the resistance if you want, who cares! No pressure, Erin. You have nothing to prove. Thank you, protective part (of mind/brain/psyche) for protecting me."
This Morning Trail Running: "I know these symptoms are MBS. Thank you, protective part (of mind/brain/psyche) for protecting me. I am so sorry you feel so unsafe, but I understand why you do. I am here for you. I've got you. We don't have to go fast or push hard. Actually, we can just walk (walking now..). See? It's okay. There is no pressure. I've got you. We are okay, we are safe. Thank you for protecting me."