Hello @varg4258, I'm glad you came to us. You want a plan, and to take action! That's great but take a deep breath too. Be prepared for the diagnosis process to take a bit of time. It's often a game of 'hurry up and wait'. Your oncology team may be able to give you an idea if this is a new cancer (lung cancer), or possibly that your previous cancer has spread to the lung. As Pam noted, a biopsy can be most helpful in determining what is driving the cancer. Knowing what's driving the cancer is key to determining what types of treatments may be most effective, and key in determining the best oncologist specialty for you (thoracic/lung vs digestive). If your cancer is related to the rectal cancer that you were facing earlier this year, then treatments may be very different than a lung cancer treatment.
If you are able to access a heath care system that focuses on research and education, they will likely have oncologists that specialize in different types of cancer. There are many good cancer centers around the US. Here is a link to those approved by the National Cancer Institute that may be helpful:
https://www.cancer.gov/research/infrastructure/cancer-centers/find