I'm a girl, and my bass drum carrier bruises my pelvic bone?!

I'm not sure if this has anything to do with me being a girl with a small frame and wider hips than a guy, but the carrier (that's supposedly fitted correctly) hits me right on my sides where my pelvis sticks out, and leaves bruises on them when I march long routes for parades.
They're very sensitive afterwards, and I often have to refrain from putting the drum on because of the tenderness of my sides.
Is there any particular reason it's doing this, and is there anything I can do to prevent this from happening?
The carrier fits fine. My back doesn't hurt or anything, and I can march without interference of the pelvic plate with my legs. It just hurts like all hell, and I don't know what to do about it.
You know, besides suck it up and deal with it.