Neck lymph nodes can be the result of tonsillitis, pharyngitis (infection of upper throat), infection in mouth, caries in tooth, internal ear infection
, outer ear infection
, eczema, dermatitis, dandruff, breast cancer, fungal infection
, other cancers like lymphoma etc. The enumerated the possibilities can be investigated or ruled out one by one by your physician and dentist.
It is difficult to comment beyond this at this stage.