Hiya Pandagirl and Welcome to the Peer Network,
There are a lot of different terms out there, and I'll admit it can become confusing at times. The key thing to remember is that regardless of what they stand for, they all refer to the same condition where repressed emotions create physical symptoms. If you find that one term really resonates with you, then by all means continue to use it. I just wouldn't worry too much about the differences between them. Obsessing about the differences between terms, and worrying about which one better fits your symptoms will only distract you from doing the work. Your unconscious is going to try and find a lot of different ways to distract you from your repressed emotions, and focusing on which term fits best is one of them. If you are really confused just say TMS. This can me either myositis, myonueral, or, the term Dr. Sopher uses, The Mindbody Syndrome.
Also, TMS can create a wide variety of symptoms. It includes a lot more than back pain, even though that is one of the most common. Dizziness, headaches and other neurological issues are also TMS. Your unconscious mind will only create a symptom that you initially view as a structural problem. Your unconscious wants you to ask yourself, Well, this isn't back pain, so is it still TMS. Asking that question is the TMS distraction at work. Begin to think psychologically and you will see progress.