What Does Pain Between The Shoulders On The Upper Back Indicate?

Hi I ve been having the occasional episode of upper back pain between my shoulder blades and mid section It usually happens when I m doing something stood up and all of a sudden I get what I call a take your breath away sharp pain right across my upper back- it feels like I m in a vice and I can t fully breathe out and can t stand up properly for a good few minutes as it reduces me to my knees . Each time I try to straighten my body up to stand, it grabs me again with a very sharp pain right across my upper back and I struggle to breathe . After 2/3/4 minutes it starts to subside and goes away. It comes out of the blue from nowhere at all. It happens every few days or so but I just can t work out what triggers it. It feels like my whole mid section is paralysed for a very short period. In 2003 I fell 20feet down concrete stairs and landed on the floor with my body at right angles to my legs - I was hospitalised for a week with what was initially believed to be a broken back but was ultimately diagnosed as muscular damage ( I was super fit physically at this time ). I then got lower back pain, worsening consistently and 5 years later in 2008 I got up to get ready to go to work one morning and collapsed in s heap on the floor and couldn t get up. I had emergency surgery on my back and was told that my L1-5 had been crushed and the substance from inside the discs had migrated into my spinal cord canal and had actually touched the cord and I was very lucky to undergo surgery so promptly. It took me 4 years to walk properly again and I now get bladder problems ( leakage ) and occasional period of not being able to move well. I wear a fentanyl pain patch . I m wondering if this is connected in any way ? I apologise for the length of this but I needed to paint a fuller picture for you . Jacqui