I have constipation. but, everytime i constipate and the poo doesnt come out, i will have stomach ache on the lower left side. ?

Abdominal cramping.: pain in the left lower side of the abdomen when straining to pass a stool is not unusual. You're probably experiencing spasm of the colon as you are trying to evacuate the stool. If this is the case, the cramping pain should go away after you have passed the stool. Notify your doctor if the pain persists or if you pass any blood. A high fiber diet may help the constipation. Good luck.