Confused about predicted treatment and other tests

scaredashell07

so my doc said that I likely had a malignant tumor about 2 cm and it spread to one or more lymph nodes in arm pit area. She was certain that it hadn't spread anywhere else and felt around my neck and collarbone. I was so upset I said I didn't want to die. And she said "don't worry, you are not dying ". How does she know it hasn't metastasized already? I said I had some chest pain on same side and some shortness of breath. aNd she said it wasn't likely from the cancer but an respiratory infection I had a few weeks before. Said it sounded muscular. I also have a small lymph node of concern on my trachea that may be biopsied but she said it wouldn't have gone to treachea before neck lymph nodes. Wondering if I should ask for other tests to check for lungs and throatnow instead of waiting for biopsy