After sleeping 6 hours, i get stabbing pain between my shoulder blades along my spine. inhaling causes rib cage pain (not sick). is my ms a factor?

Shoulder pain: Ms may be a factor, but more likely muscle strain. Also consider sprain or referred nerve root/dorsal nerve irritation.

Possibilities: Most likely answer involves degenerative disc disease or spondylosis affecting thoracic spine, and even cervical spine. A Lhermitte's phenomenon affecting spinal cord in neck could be occurring, but usually pattern is different. MS pts encounter pain at least 90% frequency, and would be worthwhile to explore with your neurologist.