What Causes Pain In Lower Back While Putting Weight On Leg?

About 4 days ago I developed a sharp pain in my right lower back and side (love handle region). It's not persistent, but it's hard to tell when it will start up. Sometimes when I place my weight on my right leg I feel the sharp stabbing pain. It also occurs when I laugh, sneeze, or bend forward. Do you have any idea as to what it is or what tests I should take?