Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with your doctor.
Without the ability to examine you and obtain a history, I can not tell you what the exact cause of your symptoms is. However I will try to provide you with some useful information.
If a Chiari malformation is minimal and there is no obstruction to CSF flow, then it would be unlikely to cause neck pain or other symptoms, including headache. Chiari malformations are not uncommon and are often considered incidental findings (just happened to be found on an MRI done for workup of various symptoms), and surgical treatment of Chiari's when they are not the cause of symptoms would not result in a benefit and could potentially cause harm.
If there are no structural abnormalities on MRI of the cervical spine, then further surgical treatment options would be unlikely to be beneficial, and are likely to cause more harm than good. Neck and back pain in the absence of structural findings (such as herniated discs, arthritis, narrowing of the spinal canal etc) are often due to musculoskeletal causes, such as myofascial pain syndrome. This causes pain coming from the muscles and connective tissue in and around the neck area. This should not be surgically treated. Rather, treatment may include medications (non-steroidals such as advil), sometimes a short course of steroids, temperature therapy (hot or cold packs), stretching and controlled physical therapy, muscle relaxants, and so on, these are best prescribed by an experienced physician, each has its own indications. If there are trigger points (spots that are very tender), these can be injected as well.
Evaluation at a chronic pain management program is recommended.
Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.