Gout is caused by a buildup of uric acid, a waste product that comes from natural body processes and can be found in some foods. Normally kidneys dispose of uric acid through urine. Sometimes a buildup can occur if too much uric acid is produced or the kidneys can’t properly dispose of it. If your uric acid levels get too high, hard, needle-like crystals can form in your joints, fluids, or tissues and cause pain.