Paul, you probably should be seen in emergency right away. Severe thoracic pain could indicate a persistent spinal leak. Imaging will determine if there is a leak and a leak can be patched.
Headache is the most reliable sign, but increasing thoracic spine pain after three days, numbness and weakness in the legs are suspicious for spinal leak. Not being able to breath is frightening.
I hope you get some help with the pain as well.
I don't have a medical background and have never had a spinal tap.