Pain in the upper back is most often caused by a problem with the muscles of the back or a problem with the spine. Upper back pain is less common that lower back pain. This is because lower back pain caused by a lumbar sprain (from lifting something heavy) is very common. Different types of physical activity can cause similar problems in the upper back. In addition, problems such as spinal stenosis (where the spinal cord gets compressed), and nerve impingement (where a nerve gets pinched are problems that you could have in the upper back.
You mentioned your normal stress test and stents. It is possible for pain in the upper back to be from the heart. Some people develop this instead of chest pain. However it is unusual and since your last stress test was normal, I will say that it is unlikely that your pain is caused by a heart problem. Back pain can also be caused by problems with the pancreas or gall bladder, though this type of back pain is often associated with pain in the belly.
I suggest that you schedule an appointment with your primary care physician
. He or she can take a more detailed history of your symptoms and perform a comprehensive physical exam. If your doctor
is concern about a major problem, you may have to undergo additional testing.