Hi. Swelling in the neck or any part of the body particularly lymph nodal swelling can be due to benign tumors , malignant times or cancers or infectious.
If swelling is associated with pain , fever, tenderness it might be due to infection.
Painless prolonged swelling might be due to cancers.
Long standing swelling with sudden onset of pain may be due to cancer also.
Next Steps
Kindly get examined by doctor and if any swelling get it biopsied or do FNAC.