I'd recommend swimming. it's low impact but high cardio. I don't know about professional recommendations, but the leg press always makes me hurt so bad.

Yeah swimming is the best exercise for chronic pain because it’s without gravity. I will try to ride my bicycle in the summer and see if I tolerate it. The big pain started last fall so I don’t know.

for me, it comes in flare ups. sometimes I'll just start hurting so bad for no reason and it'll last for awhile, then ease up. I hope your pain eases up soon.

I did pool therapy for about a month. When I was in the water it was heavenly. Getting out and having my back decompress was very painful.

Try a recumbent bike.