2 year old pain in lower left tummy when I lift her legs up

[kateonamission]

Hi
My 2 year old girl bursts in to tears whenever I go to change her nappy and lift both her legs up as she's lying down and complains of pain in her lower left hand tummy, (her left hand side, my right side looking down at her). She rubs it and cries and points there specifically.
She's a really good baby and never complains about anything so it's really out of character and got me worrying. Has anyone experienced this?
Thanks

Could it be constipation? I'd definitely take her to the GP ring out of hours or 111 (or is it 101?) as it's Sunday

Any other symptoms? Def take to dr tomorrow - not sure what the symptoms of appendicitis are? Or maybe just a pulled muscle? Hope she's ok.