Maybe see your primary doctor also to get a complete physical, full blood work, culture tests, std's. It could be anything, and chills, fever sounds like an infection or other illness, which can cause enlarged nodes, but I'm no doctor, and there can be co-diseases, illnesses with anything too. To answer the question, the Tonsil. BOT, especially HPV related, can be painless until late stages, have no palpable lump or other obvious signs, unlike tobacco caused, and are usually not found until a lymph node is involved in late stages. I had 3 flex scopes, palpable exams and nether ENT could feel or see anything, but knew cancer was there from a FNAB in two positive lymph nodes. A direct biopsy pathology showed cancer was in the tonsil.

Good luck.