Why every time after i poop my stomach hurts, sometimes my poop is like nuts but sometimes not? what can be the cause?

How much does your stomach hurt? If it is severe, you should see a GI doctor. The shape and consistency of your stool is likely related to your diet. But, if you are concerned, see a GI doctor.

While a wide variety of changes in the consistency of the stool are normal, it should not be the usual that you have pain after a bowel movement. You may try increasing the amount of fiber in your diet, but if your discomfort after bowel movements persists, you should see your doctor or a gastroenterologist for evaluation. Good luck.