Hi Domanique,
I'm learning a lot about the body and how it works right now. I've learned is that the lymph system is directly related with our adrenal glands. It could just be that the procedure sort of made your adrenals go, "whoa, what the heck is that thing poking around in there?!" You might have been a bit anxious during the procedure, and the adrenals would send out a signal to the lymph nodes to "get fired up". The body is on alert, prepare to fight!!
Did the pain go away the same day?