Dilated Common Bile Duct

I am a disabled chronic pain patient with full body RSD who recently had a MRI of my lumbar spine. On that they found that the Common Bile Duct measures 1.3 cm in diameter and they suggested an ultrasound.
I have had my gall bladder out many years ago and they have done blood work on me as recently as two weeks ago and all was fine - except for being low in Vitamin D.
The meds they have me on do keep me "stopped up" to put it delicately - but I use what the doctor tells me to for relief.
Can you please tell me what this finding means?
Thank You