My husband has mobility issues with his legs and we thought that if they could be strengthened that he might not need to utilize his crutches nearly as much so we arrived at the idea of getting him a stationary bicycle to use when he feels up to the task of exercise which might aide you in getting the exercise you seek as well :) .
Would you still be able to swim? I heard that when you work out in the pool it's easier on your body and it can be therapeutic and perfect since summer is around the corner...
Try low impact exercise, like Pilates or Yoga. My back is so bad from nearly 40 years of nursing I had to retire at 56,but I kept going. I do daily stretches in a particular order as soon as I can in the AM to take the edge off the pain (I am rarely pain free) but some days are better than others. I also garden,which is not so strenuous but is still exercise. I take 2 Flexeril at night so while I sleep I do not stiffen up. For Pain they have a new version of Tramadol (a schedule 4 Narc, but at the bottom of the list) that is time released. This is the only med I take in the morning and it has made a big difference in my quality of life. The pain is never gone but it is very bearable since I have been on it. The side effects are worse than the teeny buzz I get from them,and I am prone to constipation. I drink Yakult and it helps with that. There are ways of keeping active that does not break the back.
I have been paralyzed in different areas my porphyria and hiv don't like same thing I'm always moving and now can walk across apt have power chair and freak people out when I get up (can't walk too far ) just try to keep moving I miss working out am still a health nut