Your symptoms could well be coming from nerves being irritate in your back. The lower part of your back can refer to this area. I think scanning your back is a good plan....this may show if there is anything pressing on the nerves here, that may be causing your shin pain. A physio may be able to help, obviously they would want to get a thorough history from you and may feel that it was not appropriate to treat you until they knew that it was something that physio could help with.

TENS can sometimes be useful with nerve type pain. I would speak to your specialist / doctor about physio and the use of TENS at this point.

I hope things improve soon for you and that they are able to get to the bottom of things for you.

Good Luck, I hope this was useful.