I am sorry to say, but I think his back may be broken.
You need to get an X-Ray
Here is a link for finding veterinarians just enter you zip code or state and find one near you.

https://timssnet2.allenpress.com/ECOMARAV//TIMSSNET/amm/TNT_MDSearch.cfm?CFID=857656&CFTOKEN=44498805

Sorry I can’t do more.

Sam Pascucci