Great posting from everyone here, took quite a read to get up to date! haha. Awesome to see such high level of input into a case. I loved reading it because I kept thinking "oh I think it's probably this" and then the next post would say exactly what I was thinking!
To add my bit... A Thoracic derangement is very rare even in the McKenzie world. I really feel that you may have hurt a Wikipedia reference-linkfacet joint in the thoracic spine and this is causing inflammation and contributing to a neural tension problem. I believe some manual therapy in the form of mobilisations may be very helpful and hopefully your physio could help you with this - a bit of massage isn't bad but won't have a lasting effect on relaxing the muscles. Refrain from poor postures (this has already been said i.e. don't do cycling right away) as this can impair your healing process.
As for home exercises, From a McKenzie stand-point you can do the McKenzie push up with your hands further away from your body - this targets the thoracic a bit better, but if it is higher up which it sounds like it is then we often use leaning backwards over a chair in sitting or lying on a table and letting the head and thoracic spine come back off the edge (get someone to hold your feet if your worried about slipping off). - These exercises are great as they mobilise the joints and though are not as specific as a physio mobilising a specific segment they can do a certain amount of help.

Good luck