Sadly to say so many times those in our lives dont understand and it is just another hurdle we come up against in this battle.
There are some things I have found to work to help those on the outside looking in to have a better understanding of our pain and sometimes they work for some folks and othertimes tehy already have preconceived notions and nothing works.
You might try educating him to back pain and the diseases effecting you,print out some info and get him to read it,have even seen people print forum posts from various threads and have family read as then they see it isnt just you that suffers.
Take him to your appointments with you,share your thoughts but try to leave the whining at bay and that is difficult at times as I hurt I whine,natural but useless most times so I whine to myself! Lol
I am a far better listener to my own whining then anyone in the family anyway!
Try to encourage him to be a particpant in your needs and issues as alot of time the fear of the changes they see in you are enough to push them into an outsider,we tend to get all wrpped up in our pai issues and push those around us completely out of our lives and this is a normal process and it takes work not to do it. How many times I wish everyone would just go away and leave me alone in my misery! We cant hope to hold together a relationship of any kind letting ourselves do this to the point we are spending all of our time alone and isolated. It is necessary at times but dont let it become a habit and it doesnt mean you have to spend every waking hour sharing yourself but it is a quality issue versus quantity.
He may fear your pain your health issues and is putting that out in a not understanding you way.
As for the injections be careful what you wish for again and ask one of your Docs about them and and see if they think they would do any good just yet.
Good luck to you and I certainly hope you find some relief in some way and alot of times for us it is a very long and very drawn out process of finding the right Doc for us.