4yr old boy wakes up wit pain at midnight goes to washroom passes small amount of stool with gas and sme mucous. Wat cud b this? Constipation colic pain

Abdominal pain. It is not uncommon for children to get some gas pain, possibly backed up behind some stool. If the pain resolved after he had the bowel movement, it's probably fine. If it keeps recurring or worsens, he should see his doctor. If there is blood in the stool, or he starts vomiting, call the doctor.