I've never bothered with CST, but cranial osteopathy is my primary care and it's probably the most likely place you can get help with the cranial symptoms you've described. CST is a "product", one of the tools of cranial osteopathy, packaged by a cranial osteopath for teaching to therapists who practise it under licence. If you've never obtained a comprehensive structural diagnosis I would recommend starting with an expert cranial osteopath (in the US look
here for someone doing 100% OCF), who is a university-trained professional able to make a full structural assessment, determine which tools to use, and gauge how your body responds to their intervention. The limitations of therapists are that they typically are only able to use a limited number of tools relatively blindly, and their limited diagnostic skills mean if the therapy doesn't work (or even if it does), you don't learn much about your health problems.
My strategy would be to get a full structural diagnosis from the osteopath. If they find nothing of significance then CST is probably not much use, and hopefully they could suggest other avenues to explore. It's pretty likely though, given your symptoms, that they'll find things to work on and you could start treatment with them. If all they are doing is what your CST therapist could do then if the CST is cheaper and more convenient you could consider doing that instead. I'd expect you'd be a complex case though and the osteo would be needing to give you more than just CST; I'd be surprised, even if you have what is fundamentally a structural problem, if CST alone could fix it. One thing you must not do, unless you like wasting time and money, is see both in parallel, as the CST will interfere with the osteopath's work and confuse the feedback your body gives them from the previous treatment.
Note that if you have a complex and deeply established structural problem it could take years to unwind, and they can't reliably predict how long it might take, so in deciding whether to persevere it's more a question of how significant your structural problems are to your health and whether your body is fundamentally improving, rather than setting a time limit on by what date you should be healed.