My daughter has a strawberry on her back, has anyone ever heard of it causing pain or being painful?

She has had this since the day she was born, almost five years ago, and it was very raised on her back. Her doctors said it was just a birth mark and would eventually smooth out as she got older. It is now flush with the skin on her back, but last nite she was complaining that it was hurting. I have looked online and am currently awaiting her doctor to return a call, but was wondering if anyone had any first hand knowledge or has one that has ever caused them any pain.
Thanks.