Without having access to the actual radiology images and/or report, it is difficult to say. Two endometriums sounds like a uterine duplication anomaly, such as septate, bicornuate, or didelphys uterus, just to name a few. If further characterization is desired, MRI pelvis would be a reasonable next step but this is a conversation you need to have with your doctor. MRI could also be helpful ruling out adenomyosis, which can present with an enlarged uterus with painful, heavy periods.