I think the most important thing for you to do is trust the doctors. If after all the exams and tests and scans, they have ruled out any serious physical abnormality, you have to be open to the idea that these symptoms are of psychological nature. Pains are very common among anxiety and depression sufferers. Start focusing your efforts on how you can relieve your anxiety and panic instead of searching for other causes for your symptoms.
Half the battle is just accepting that anxiety is the root of your issues. I know. I've been there. I have convinced myself I was suffering of many various illnesses in the past. It seems the more I thought about a symptom, the stronger it got. Once you start attacking the real problem you will start to see improvement.
We've all shared similar experiences and are here to help.
Best of luck. You WILL get better.