Welcome to HCM
We understand your concerns
I went through your problem description. I suggest you not to worry too much. I know so many people with weird complaints. They run pillar to post investigating themselves. Always to find that they are clear as a whistle. I call it hypochondriasis
When you are sure that every test is negative for any physical problem, why suspect it. You cannot suspect every doctor who asks for investigation. You can't suspect every lab. Believe them and forget that you have this pain. Because that pain is non existent. You just feel it due to your preoccupation with it. Find a psychological counselor for counseling. I can help you through healthcaremagic if you desire so.
Hope this clears your doubt. Available for further clarifications.