What is wrong with me? Doctors, nurses, anyone who can give me suggestions to ask my doctor.?

I am not a doctor, but you need to get a second opinion until the doctors find something. The average human heart rate at rest is 60-100 beats per second. I thought maybe it was anxiety from worrying about your thyroid. Go to another doctor and have them test you for everything. I never heard of a test for cancer, but like I said I'm not a doctor. Good luck and I hope you feel better.