What is a sinew? Where is it on the foot? Pain on left foot for 10 days...I have useed rice during that time to try to make it better.

Many possibilities. Foot pain could be as a result of many different things. A thorough history and physical exam and possibly some laboratory and radiology exams are needed to determine the exact cause. Causes of pain may include: trauma (fracture, sprain, arthritis), infection, metabolic conditions (gout), musculoskeletal or biomechanical abnormality and neurologic conditions (neuropathy).