Hi. i have enlarged and severely painful lymph nodes to the right of my groin but also pain from lymph nodes down my whole leg. my q is why down leg?

See your doctor: Sounds like you need some tests done and should see your doctor.

Pain + enlarged node: Pain down the leg could be from the nodes physically pressing on the femoral nerve that goes down the leg or pain could be due to pressure or irritation of the sciatic nerve at it's origin in the back then travel to femoral division of the sciatic nerve which now brings the pain down the leg via the femoral branch of the Sciatic nerve. Interfering with blood supply to leg another possible cause.

Radiating pain: and the problem could be down there, the lymph nodes in the groin drain parts of your lower limb, kindly see your doctor or go to Urgent care, best wishes