A small disc herniation usually causes a deformity of the 'sac' or spinal fluid space around the spinal cord, rather than indenting the spinal cord itself, and I suspect this is what the actual report showed?
In that case, it is probably an incidental finding and is not causing your symptoms. I cannot give you a definite answer without looking at the MRI.
Other possible causes might include another lesion in or compressing the spinal cord in the higher
thoracicEchocardiogram
Lung needle biopsy
Thoracic aortic aneurysm
Thoracic ct
Thoracic organs
Thoracic outlet anatomy
Thoracic outlet syndrome
Thoracic spine x-ray
Vertebra, thoracic (mid back) or cervical region (should be identified on MRI), an abnormal blood vessel malformation around the spinal cord (sometimes not seen on MRI, called a dural arteriovenous malformation) or a problem with the peripheral small nerves causing a painful peripheral neuropathy and an autonomic neuropathy(due to for example, diabetes). I cannot be any more specific without evaluating you.
If it is due to a spinal cord problem and you have bladder/bowel symptoms, you will have an abnormal lower limb neurological examination.
Good luck with your appointments
PW
Painster