I had mri of throastic in june and in august chest x ray. mid upper back still hurting. could they of missed cancer?

Possible, unlikely: Assuming well performed, well read by competent radiology specialists, it is unlikely that cancer would be missed. Could be other causes not seen with the above mentioned tests. Follow up with md.

Possibly: Mri and chest x-rays are not 100% sensitive. It's possible that the MRI could have missed cancer. If your symptoms are not resolving in spite of medical therapy, then you should look into getting re-evaluated. I think cancer would be low on the list at your age, but certainly not unheard of. The pain is telling you something, so be sure to get a solid diagnosis.

More follow-up: Please see your doctor for further evaluation. Missed cancer unlikely but need to find reason for pain. Properly performed thoracic spine MRI read by a qualified radiologist should clear the actual vertebral bodies, but depending on field of view, other areas of the chest will not be seen. Chest x-ray is a fine screening tool but chest ct may be helpful to view your entire chest and back.