I have leg pain and foot pain on the left but not on the right. Is that strange to be only on one side?

Not realy? You could on sided foot and leg pain, the cause for that could be from your back or from arthritis in that side or from injury one side. Thank you.
Not unusual. Your 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), circulatory, musculoskeletal or biomechanical abnormality and neurologic conditions (neuropathy).
Limb length. Foot and leg pain does not have to be symetrical. There are many different aliments that could occur that cause foot and leg pain on one or the other extremity. The most common cause of unilateral foot pain could be a limb length discrepancy where one leg is a little bit longer than the other causing the longer leg to overpronate. Pronation is a destructive motion that causes many pathologies.