This may not be AT ALL helpful, but just wanted to share...

I've had an infection in one of my testicles for several months. Never, ever had any chronic infections prior. Finally went to doctor and starting taking antibiotics.

Strangely, recently, and just before I finally decided to see a doctor, the lymph nodes under my arms (so it feels like) started to ache a bit on a daily basis.

Hi, I am a dental assistant, so maybe I could be of some help. I have seen many abscessed teeth cause the lymph nodes in the throat to swell, but never under the arms. But everyones bodies react differently, so I would definitely have it checked out. And if all possible, I would recommend getting the tooth removed as soon as you can. I know its hard, but maybe you can find a dentist that has a payment plan. There is a program called Care Credit. You can find it online, its like a medical credit card. I use it, and it works well. There is no interest on it for a year, but there is a catch. You have to pay every payment on time, otherwise, they will back charge you for all the interest. But you can use it for vet bills, medical, dental, cosmetic, and eye surgery. Hope this was helpful.