Intense back spasms off and on for 2 wks in the mid-back in muscles that run along spine. hurts to breathe, lift arms, laying on sides. what is wrong?

Persistent spasm: There can be many causes for this type of symptom. If you lifted a very heavy object, were playing contact sports, or were involved in a motor vehicle collision, this could be due to a vertebral compression fracture or rib fracture. If you have no history of trauma, then muscle spasm is more likely. If short of breath, this could be pulmonary embolus. You should be examined by a doctor.