I agree with Ed34, see a doctor. I've had both heart and gastrointestinal issues and surgeries, and it sounds like an issue with your esophagus/stomach. I'd see your GP first to be evaluated.
Your symptoms are classic for a spasm in your esophagus, and yes, they are very painful. If this is suspected, they have a couple of tests to prove it. One is what is called a Motility test, the other an Endoscopy.
I'd try to get something like Ensure or Jello down. But, you must see a doctor. Hope that helps, stay in touch.
I assume you've seen a Doctor as you haven't eaten for so long. This could be so many things that you really need to see a Doctor and probably have some tests.