Can a herniated disc in your lower spine cause middle thoracic back?

No. There should not be any pain your thoracic spine from a lumbar herniated disc.If you have degenerative changes at lumbar levels, you may have them at your thoracic as well. One caveat, and a very rare one, is if you had enough of a herniation in upper lumbar areas to damage the cord and cause a syrinx. However, this would have been seen on MRI and you'd have more symptoms. Incontinence? Yes=er.