Does swelling lymph node in groin (hiv) cause swelling and discomfort down one side of leg & foot?

It can, but. it usually works the opposite way. An infection in the toe,foot,leg, causes swelling of L Nodes in groin. .
See a doctor. If you have anything in your groin that could be blocking the flow of blood either into or coming from your leg, there is always a worry that you can develop a blood clot, also known as a deep vein thrombosis, which can be very dangerous. It's possible that you may also have a infection. Regardless, see a doctor soon.