I have a burning pain all the way up my arms and down my back, what could the underlying reason for this be?

Few. Among them; disc herniation or spinal cord syrinx. Would consider a cervicothoracic mri.
Several causes. Your symptoms are a bit diffuse for a simple answer. Multiple diagnoses can explain your symptoms. Burning into the arms and back can be from the following problems: disc disease in your neck or thoracic spine, ms, inflammatory problems (lupus, etc), and/or polyneuropathy (from diabetes, etc).