Yep, swollen lymph nodes for sure. I remember Alex also saying he had issues with this. For me, it was mostly my tonsils, who have valiantly tried to save me from every foreign invader they’ve ever met. I also had some intense muscle tightness in the back of my neck for a while. You can kind of poke around (lightly!*) and try to palpate whether the sore areas feel round, like little beans, or more ropy. Little hard bean feeling = lymph nodes. Hard ropy = muscles. (Generally.)
*Don’t push aggressively on your lymph nodes when your body is detoxing. They’re doing a job, which is collecting gross shit to get rid of it, and you can potentially push the toxins back out into your system if you’re squishing them (which is counterproductive, of course).
Alex found this video (I think) a few months ago and it helped both of us a bit: http://www.youtube.com/watch?v=QA-wi0d7-Ro
Also, here’s some info about acetaldehyde in the context of hangovers. It’s applicable to die-off, as well. http://science.howstuffworks.com/life/human-biology/hangover4.htm