What Causes Severe Pain Between Scapula And Numbness In Feet?

75 year old woman with hx of colectomy, severe pain between scapula on the left, pneumonia for 4 months, numbness in feet, appears to be progressive leg weakness, now needs a walker to walk in past 2 weeks. Very unstable, 3 falls in 3 days. Going in for an NCV tomorrow. No MRI ordered. Sputum culture from lungs negative, EKG negative, CT scan to thoracic spine negative. Any thoughts