I have had swollen lymph nodes in neck/groin for over three months now. also, day after drinking alcohol i have painful swelling in neck. why?

Exam: You must be examined and obtain specific blood testing and imaging for further evaluation of neck masses. Stop alcohol now!

See a physician: Lymphadenitis or swollen lymph nodes is due to viral or bacterial infection. The swollen lymph nodes caused by cancer is not very common condition. I don't think that your case is any different. Rec.: see your pcp for further investigation.

Need further eval: Any persistent swollen gland(s) should be evaluated further. Painful nodes after drinking alcohol is not a common feature of lymphoma- it usually points to other things; but it has been described in Hodgkins Disease. Although most likely due to something else, Hodgkins is seen in Your age group. Please get checked out.