After piles surgery and being constipated. is it normal to have to push your stool out?

No: Problems like this are never normal, but they are common. Narcotic pain medications after surgery can contribute to constipation. Check with your doctor to examine your diet. This may be contributing to your constipation problems in the first place and may need modification.

Yes : There is not much else u can do at this point but to push. Key is to avoid constipation with lots of water, fiber, softeners, laxatives etc.