I would DEFFANITLY get a second opinion!
I don’t mean to scare you and I am not a doc. By any means, however you are describing some very typical signs of lymphoma.
I have swollen glands and a sore neck all the time. And I will be getting my largest lymph node removed and will have a biopsy tomorrow.
I had to go to three different doctors before one decided that it was time to take them out and see what is going on.
If it where me I would go to another doctor ASAP!
Good luck, and let us know what you learn.