Since 2 days, i have been having severe pain which shoots down my leg, when i stand or bend down from the hip . i have severe knee arthritis in the same leg. what shouldi do?

See below: Talk to your doctor, this could be a simple as a slipped disk in your back. A scan should rule this possibility out. Sometimes these areas can be come inflamed and trigger nerve pain that radiates down your back and leg.Can frequently be managed with nsaids and a planned exercise regime, but please check with your md.

Get it evaluated: It is difficult to draw any conclusions from your description. Is it radiating down the front, side or back of the leg? Have an orthopedist evaluate the issue.

Consider MRI: Of your lower back and an evaluation by your doctor.