Is my kitten in pain?

i brought a kitten couple days ago, she's 8-9 weeks old. her mum died a week ago, and so she had to feed off another cat thats havng kittens. i give her meat chunks and biscuits and kitten milk. but when she stoops to go the toilet, she meows. she just had a poop so i know she can do it. is the solid food making it feel strange to her? she prancing around alright and sleeping so ?