"A PET cannot distinguish between cancer and not-cancer."
Because the areas that light up can be cancer, or not-cancer (increased activity in the cells from non-cancer causes).
There are even some benign "lymphoproliferative disorders", all of them are not necessarily cancer. Some are very mysterious.
"IF THIS WERE lymphoma... would this be considered stage 2?"
Hi, that's probably Stage 1, as they are all in the same area.
But that is a very big "IF".
More important is: "Sarcoidosis could have a similar appearance is also included in the differential." A PET cannot distinguish between cancer and not-cancer.
"what’s usually the next step?"
To choose the most suspicious node and determine what's inside it -- likely with a guided needle biopsy. The nearly oval one (1.5x0.8) is not very suspicious because it's oval. So that leaves the 1.3x0.9 one, if it is accessible (e.g., not near a nerve or blood vessel). My guess: the odds are that the biopsy would turn up negative.
If your doc is not particularly alarmed by the PET result, they might just wait and do a CT of the two large nodes in a few months to look for any major changes. You'd also monitor yourself to make sure there aren't any new bumps appearing anywhere.
All that being said, there is still something that prompted the PET to be done. Why did the doc order the PET? Coughing and chest pain?