I don't really understand what you mean by "a half inch to through out the neck", but depending on the exact location, it could be a number of things.
If it's on the side of your neck, either below your jaw or just behind your collar bone, it could be a swollen lymph node, which is typically a result of your body fighting off an infection. Typically my lymph nodes will swell up when I have a cough/cold, but they've even grown to Golf ball-size when I contracted cat scratch fever.
If its your Adam's apple that is swollen, then it could be a goiter, which is a swollen thyroid gland caused by an iodine deficiency.
Xrays and CT scans
no.
Yes.
MRIs or CTs they are just pretty much like xrays but different machines and things are used to watch and see how your brain is functioning
If the headaches are as horrible as you say, no. When the sinuses are infected they produce mucus which creates the pressure which creates the headaches. On xrays (or CTs) normal sinuses look dark gray or black, when there is an infection it is white. Very hard to mistake. Headaches have to be from something else. Keep looking.
Yes, they can perform blood tests, xrays, CAT Scans, MRI. Bone density test. They might also do a bone marrow test.
radiolucent allows x-ray pass through radiopaque does not allow it to pass through
A normal chest xray but angled up a little and a smaller area at the top of your chest.
Yes you can very clearly and its just so amazing!
a grid is a device placed in front of the image receptor which only allows xrays to travel directly through from the tube and prevent xrays which have been "scattered" from passing through to the image. This gives a much clearer resulting image. Grids are generally only used on thicker body parts where scattered xrays are more of an issue
It certainly is a huge factor since doctors have to read off Xrays and image scans and they have to accurately read off charts. If a doctor doesnt have good vision it certainly increases the chance of error
How do you know its not broken, could be fractured. Take the dog to the vet for xrays to be sure.