Hi  Welcome to Healthcare Magic Forum  You seem to be having Cervical lymphadenitis..  This presents as a tender, smooth lesion in the cervical region .  It can be associated with fever and other systemic symptoms...  It is important whether you are also suffering from any other problems like Upper respiratory infections, sore throat, cough or tonsillitis,,,As such lymph node swellings usually occur as a protective response in our body in order to contain any such infections..  Also, if it is an acute swelling, as it is in your case, then it is relieved as the primary infection heals or is treated,,  So you might need a course of oral antibiotics along with pain killers..  I would suggest that you see a general physician who can locate the focus of infection and treat you accordingly..  Hope it helps  Wishing you speedy recovery  Dr Geetika Paul