What could be the reason why the lymph nodes in my groin are swollen?

Lymphadenoapthy: Swollen lymph nodes can be casued by several things, infection and underlying illnesses are a few examples. See your dr. For an evaluation and assessment of the condition. Good luck.

Monitoring Centers: Lymphatic system absorbs/carries things too big to go into the arteries/veins like bacteria eaten by white cells/digested food. Lymph nodes "taste" the lymph everywhere for bad stuff 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.