What does it mean when one set of lump nodes stop hurting but another set starts to hurt?

Lymph node swelling: Lymph nodes are on us to help control infection or at times control the spread of cancer. If a systemic infection occurs, it can lead to multiple groups of nodes swelling, with associated tenderness. As the infection subside the lymph nodes also become smaller and less tender. For multiple groups to be involved, may indicate a common source or a more serious problem.