You may have been wearing the same tight pants for years, but your body may have grown and now the pants feel tighter around the abdomen. Also maybe you are wearing a different belt that has a much larger buckle?

Wearing tight pants over months to years should not by itself cause abdominal pain. Wearing tight pants, underwear, and thongs have been found to increase infections. Examination of your abdomen and a few more questions about your signs and symptoms would be important too.