Can I ask where the pain is?
I've been through much trauma in my past and it very possible to past traumau to manifest as ohysical symptoms, but they're are conditions that aren't easy to find like Interstitial Cystitis and endometriosis, Irritable bowel syndrom.
If it's abdominal pain and your sister feels there is something wrog then she should chalk it up to psychosematic pain and keep getting it checked out until someone find teh answer.
As for pain in other areas of the body, theer are also other conditions not easy to diagnose but I'm just taking my personal experience as an example that although I've experienced much trauma in my abdominakl area there was truely something wrong.
And the past traumas can exaterbate the pain and the pain can exaterbate the amxiety I have...but the point is that there is really something wrong and if your sis feels that there really is something going on just keeo trying to find the problem.
But it is of course possible that trauma, depression, anxiety..psychological issues or traumau can manifest into physical symptoms as well as pain.
Amph
It is certainly a strong possibility.