How can you tell if your lymph nodes are abnormally enlarged in your neck, armpits or groin?

Get checked: If lymph nodes are enlarged for no apparent reason, and remain that way for any significant duration of time, are hard to the touch, are quite tender, increase in number, or are accompanied by other symptoms it might be a good idea to have a professional examine you.

Monitoring Centers: Lymphatic system absorbs/carries things too big to go into the arteries/veins like bacteria eaten by white cells and digested food. Lymph nodes "taste" the lymph for anything bad like bacteria/viruses/cancers, etc. When it detects a problem, it alerts the immune system and your body reacts. They enlarge in response to the inflammation they create when they react. They shrink when all is well.