Forgive my lengthy response, but I like to be thorough...
If I remember correctly when I got my .40cal Green Mt. barrel to make a two caliber swap barrel gun... the .36cal was not being produced. It didn't matter at the time, as I wanted the .40cal anyway, BUT you may want to confirm that information.
Despite the lower opinions of some towards the Italian/Spanish manufacturers products, I have never had a problem due to quality, or lack thereof. While they aren't fancy, they do tend to function... and some of them do shoot quite well.
Since the nature of your request involves your health and wanting to remove the potential for causing further damage to your body... Perhaps you could get by with a .40cal, but then the gun may have to be a little too heavy to soak up the extra recoil.
I don't remember seeing anyone mention the Traditions Shenandoah, which if still in production was available as a .36cal percussion and was also made as a flintlock. The nice thing is 5lbs of "Triple-Ought" Buckshot and you've got lots of ammo for very little cost. As you note, both calibers can be shot with very low powder charges or pushed hard and with virtually zero recoil.
I prefer the .36 over the .32, even though the .32 shoots well, I like the .36's extra lead at practically the same high velocities. Both guns are fairly inexpensive to operate, it's a shame that they are not more popular than what they are... but both calibers aren't usually legal for anything but small game. (FYI, in West Virginia a minimum of .38 caliber is required for deer--so my choice of .40cal makes sense now, right.)
Deer Creek used to have .36cal Bobcats for sale for $159 and .32 Squirrel rifle kits for about the same money. I really don't know what they have on-hand right now, as most people know that sidelock muzzleloaders are becoming increasingly hard to locate. I owe them a call anyway about some parts--while they still have some for older CVA guns. Their phone number is 765-525-6181
Sorry I wasn't more help, but give Deer Creek a call and see what they can do to help you. They do not have a website or an Internet presence (no e-mail). They are good folks to deal with, and I have never had any issues that were less than excellent--with their merchandise, or themselves.
Good luck, and may you mend quickly & properly.
WV_Hillbilly
PS As far as finding used guns goes, you can try the auction sites, and maybe in your region it's easier to find the small bores in the local gun/pawn shops. Where I live, sidelocks are very uncommon now and most guns don't stay very long for sale. Gotta make the best decision you can during your first impressions, 'cause I find that waiting a day or two to make sure, and then calling back to have them "hold it", or going back in person is futile... it WILL be sold.