What Causes Pain Radiating Between Pelvis And Groin Area And Upper Leg Tingling?

My sister has had several bladder infections and kidney stones. She is currently having back pains going through the pelvis to the groin area. Along with sharp pains, pin pricks, tingling, in the upper leg. Her Dr. hasn t found anything wrong, and her last blood work shows clear of infection. Please give her some direction to turn for help. Thanks Teri