If your head hurts after pooping it could be that you're straining too much to poop.
You could be slightly constipated and when you push really hard to get the poop out then it can lead to head pain and cause your head to hurt after pooping.
The head pain after pooping should go away within a few hours or so.
You could also have gastrointestinal problems that can make it harder for you too poop which can lead to the head pain.
If you continue to experience head pain or headaches after pooping then see a doctor to make sure you're okay and nothing bad with your intestines are happening.
Most times head hurting when pooping is caused by straining to poop so avoid straining as much and see if you do not experience the head pain or headaches afterwards.