The place you describe (right under your jaw) isn't where your thyroid is. The thyroid gland is slightly below your Adam's Apple.
Most thyroid cancers are very slow growing and wouldn't spread to your internal organs so fast. Also, thyroid cancer rarely alters the levels of thyroid hormone in the blood, so it shouldn't cause baldness.
I don't think that the pain is your liver. It could be your gallbladder, which is right above your liver, below your ribs on the right side. Does it hurt to press on that? Does the pain get worse after you eat fatty foods? The pain in your chest could be what they call referred pain from your gallbladder. But the fact that the stomach pain went away and the chest pain stayed makes that much less likely.
Go back to your doctor and insist on a complete physical with blood tests and a scalp sample (something is making your hair fall out). Also ask for a chest x-ray. Don't let the doctor dismiss your symptoms and tell you they will go away.
Write down a list of all your symptoms, when they started, the severity, what makes them better or worse, and which have gotten better. Take this list to the doctor. If your current doctor won't listen to you, get a second opinion.
Good luck. Let us know what you find out.
