I have had this horrible pain in my neck in the back to the left side

Sounds like something got screwed up during the thyroid surgery. I say that because I have suffered every day since 2012 due to botched thyroid surgery at major NYC cancer hospital. I hope you got all your records and disks w/reports. Did another specialist to look over them and see if something happened. (Not that it would be mentioned, as I also found out!)
I'm sorry you are going through this but I can relate in my own way.

@sandra1775 Hello and welcome to Connect. The pain you describe in your neck could indicate a spine issue. Since this pain gets worse when you bend your neck forward, that kind of suggests a possible problem with a disc. The spinal cord has to glide up and down inside the spinal canal fluid when you bend your neck. Bending the neck can increase pressure on a problem that is there, causing increased pain. When discs deteriorate and collapse, the vertebrae bones get closer together and can pinch the nerves that come out between the vertebrae. If your disc has ruptured, the squishy disc material that comes out could be putting pressure on a nerve root or the spinal cord and there could be bone spurs. Burning pain can indicate nerve compression and it can be like electric shocks. Has this pain gotten worse? Has a doctor tried to evaluate why this is happening by doing some imaging, perhaps an MRI of your cervical spine? Having had a prior surgery on your neck causes scar tissue, and that can cause tightness that pulls on the spine. If you are having muscle spasms, the spine might become straightened and loose the normal curve it is supposed to have and that can also increase pressure on an existing problem.

I am a spine surgery patient, and I had spinal cord compression in my neck with a ruptured disc and bone spurs, so I have had some of the same symptoms. It is worth checking out because a spine problem can sneak up on you and cause permanent damage if left untreated. I know you have lived with neck pain a long time. Have you had an injury like a whiplash? I can tell you that fixing a spine problem surgically can be a good thing. It was for me and made a big difference in my ability to coordinate and move my arms properly. Of course every case is different, but it is worth seeking an answer.