Welcome to HCM
We understand your concerns
I went through your problem description and symptoms and history. Every doctor you visited concluded that you have no severe medical conditions. All tests results came out normal. This is where you have to believe in your doctor or sometime self. There is nothing to worry should make you happy and return to normal routine without worrying about anything.
Doctors do suggest several tests and several differential diagnosis because they want to be doubly sure. When those things happen we always pray god nothing could be wrong. Once tests are OK we thank god. But in your case you are still anxious even after all these.
I am sorry to tell you that your problems corresponds to anxiety
disorder, more suitably, hypochondriasis
. Worrying about diseases even without them. Do some stretching exercises and have balanced anti acidity diet, drink enough water and fruit juices, and don't worry, leave things to god, for you and your doctors are just a human beings.
Hope this answers your query. Available for further clarifications.