After I swim I get swollen lymph nodes for a couple days (on the right side of my body) in my groin area, neck, & armpit. I'm not sick at all.?

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.
Interesting..... I'm assuming that it goes away after those "couple days"? I don't know why you would have one-sided lymphadenopathy (swollen lymph glands) unless it has something to do with contact in the water, like chlorine. I suggetst that you go to see a doctor while the glands are swollen so that he can check you out (maybe make your appointment and go swimming first!) any other symptoms: rash, fever, etc?