3 year screaming in pain and cant poop

My 3 year old just got home from her aunts house and her aunt informed me she hadnt pooped all weekend. Which is nothing abnormal. However she gets home and says she has to poop. So she goes to the bathroom and comes out in tears as if she had a accident. However she didnt. She has to poop but it hurts to push. I can see the poop and now she is leaned over the couch with her pillow as if she doesnt feel good. I feel so bad for her. What can i do for her to get it to come out quickly? She wont drink her apple juice which she loves. Help.