Sorry about your back. I know full well from my own spine that it sucks to have back trouble at any age, but as young as you are... I pray you fully recover.
Back back, bad shoulders, bad knees, arthritis everywhere you can have arthritis... I'm a worn out ol' fart.[8D] Had to pass all my longbows and recurves down to my son because I always hurt myself when I try to shoot them. I still get out the wheelbows pretty often but not as much as I used to.
Crossbows let me shoot as much as I ever did. I've decided midieval crossbow replicas are my niche. I used to make and shoot selfbows... now I make and shoot crossbows.