I have an itchy and slightly tender lymph node on my neck, under my chin. it's on 1 side. the lymph node is swollen. ?

Possible insect bite: Swollen lymph nodes seldom itch. It's possible that you got an insect bite, which itches, and a nearby lymph node may have become swollen and tender. If symptoms increase, or don't resolve in a few days, it's best to see a physician. Meanwhile, warm (not hot) compresses may hasten recovery. Avoid scratching or squeezing the affected area.