If you feel much on your body you will probaly find many lumps and such, i myself have lymph nodes swollen in my groin, under my elbow and in the neck, both leukemia and lymphoma causes the lymph nodes to go very big (over 2cm) and often hard and inmobile.

You probaly also have more than one lymph node swollen in the groin on both sides, you can feel that they start up in the belly and goes down into the groin, they can be longer than what they are sideways in the groin i think? also it's good that you don't have any night sweats or weight loss, but a bloodwork would show if you had leukemia and for lymphoma the doctors feel on the lymph nodes first and if they feel wierd they send you to an ultrasound.

also it seems normal for lymph nodes to not go down in size but i'm not a doctor, like i have said before both my dad and little brother also have swollen lymph nodes that doesn't go down in size.

Hope you have a great rest of your day/night!