I've had chronic swollen lymph nodes for many years (seen on multiple ultrasound images). Doctors have shown no interest in investigating further. Since I'm still undiagnosed after an odyssey of lab testing, I want to bring this topic up during my next visit but I don't know much about it. What are the possible causes of chronic lymph node activation? How do they relate to symptoms that resemble CFS? Is there any relation to very low ESR? Is there any relation to mildly elevated monocytes? What lab tests are useful?