This still might be caused by referred pain from nerves in your spine. Usually, a herniated or ruptured disk will lead to these symptoms, but arthritis and malalignment (even very subtle) can press on "trigger points" in the spine leading to back pain, shoulder pain, and even referred pain in the arm. It may seem silly but chiropractic treatment has been effective for a lot of people when otherCustomerdiagnostic tests have failed to find a problem. Chiropracters are usually very knowledgeable about different types of spinal problems, and the appropriate treatment for each. Electromyography might be a good next diagnostic tool for you. If narcotic pain relievers are not sufficient, TENS units (electrotherapy), and medication for nerve conduction pain (such as gabapentin and magnesium oxide) might be beneficial, as well as corticosteroids or anti-inflammatories. Until you can be seen, Aleve and Ibuprofen available over the counter can be used to treat pain and inflammation symptoms.
I hope this helps!