I have had a lump on my neck for 4 years. dr says i do have swollen lymphnodes but not of clinical sig. what could be the cause?

Probably neg.: A lump in the neck for 4 years unchanged is probably benign. Depends on where in the neck , the size and texture. A midline mass may be a thyroid nodule and if solitary and cold needs removal, Lymph nodes of concern are mostly among the jugular region nodes and if lesion feels soft may be a lipoma that is unchanged or even a salivary lesion if present just under the jaw in the submax gland.