Tamoxifen / spots on lungs

Hi, I just found out this week by xray I had a 7mm spot on my lungs. That led to many more tests like CT, blood, ultra sound and pet.
All tests except the pet and xray were clear/normal.

The PET shows 2 lymph nodes (one by each lung in the center of the chest) by the lungs light up. The lung nodes light up also making several small spots on the PET. The 7mm spot showed up on the pet but none of the doctors could find it to show us.
The doctor says its too early to tell if its cancer or something else then set up an appointment with the lung doctor for 2 weeks later. She thinks the spots are to small to sample to tell if its cancer. She has no urgency since if it is breast cancer in the lungs there is nothing that can be done except extend life by medicines.

I have been on anti depressants in the past and currently I'm not taking them. I have asthma and know based on a Mayo Clinic study that I am in a higher risk group but always thought if it came back it would be in my breast again. I had a ping pong ball removed one year ago then pre cancer on the other breast removed in Feburary of this year.

What do you think about Tamoxifen after spots? I am worried about the side effects like hot flashes and damage to my hormone system.

Has anyone else been in this boat?
I am stressed.
Thank you.