Thanks for writing to H.C.M. for your query.
I have gone through your your query regarding multiple lymph nodes on neck for last three month. Though they arises after severe sore throat
Considering your complaints I would like to tell you that lymph nodes of neck wnenever get enlarge there may be infective pathology going on in it's draining area. This draining area includes entire head and neck. Second possibility is of disease of gland itself.
In your case possibility is of -
(a) Persistant throat infection
(b) Disease of lymph nodes itself.
To confirm it you should do these investigations-
(1) Culture and sensitivity of throat swab.
(2) X-Ray chest -P.A.view.
(3) FNAC from cervical lymph node.
After this much work one could find out the real cause of lymphadenopathy
and that may be manage accordingly.