Hi, welcome to HCM.
Lymph nodes are structure which drains particular area of body. It mainly has drainage
of infective or waste part which is mixed in lymph fluid. It has protective function . They are scattered throughout body.
In neck it is divided in 6 group. Details of which is very complicated to understand. You have lymphnodes
at one of the group. Its size is less than 1 cm which is considered as insignificant. In short there is nothing to worry to much.
Hope I have answered your query.