Welcome to HCM,
After going through your history,You have chronic low grade fever
with Lymph nodes in neck( Cervical region).
You have constitutional symptoms and you should not ignore your health, please visit your Physician and after physical examination workup CBC,FBS,S. Creatinine,an X ray chest and if required FNAC or excision biopsy of Lymph Node.
Your further line of action depends on result of such investigation, we need to know cause like any infection or Tuberculosis
,any kind of Lymphoma, Hodgkin.
If nothing comes then proceed to CT scan Chest and abdominal Ultrasonography
You can always take second opinion
Please take care