Make sure you stay well hydrated by drinking plenty of fluid - about 2L per day, especially while recovering from surgery.
If you are taking narcotic pain medication, you should also take a stool softener which may help, such as colace (docusate sodium). And most of all, don't worry, the poop will come out soon. If the problem gets worse, call your surgeon. Hope this helps!
Would you like to video or text chat with me?