Swollen cervical lymph nodes for 5 month now havnt shrunk or grew normal CBC doctors not worried does it mean cancer?

Not likely. Lymph nodes in the neck enlarge for lots of reasons. Often it's infection, sometimes immunizations. If they're small (< 1/2") they may just be scarred from a previous infection. Cancer may grow slowly , but typically if they were cancerous nodes they would have clearly enlarged over 5 months with no treatment.
FOLLOW UP REQUIRED. Swollen lymph nodes may mean significant problems, but the majority of time this may simply be the result of a viral infection. Mononucleosis results in prolonged swollen lymph nodes. Your physician should be evaluating this ongoing problem; possibly further testing in order.