Hi. I had backsurgery and had a lamenectomy. For a few years, everything was pretty good, just some muscle problems. I found water aerobics great at the time, but only 2 times a week. Three was just too much. Also walking is good, unless of course, the sciatic nerve is causing leg pain and weakness. Now, my problem is different. I tried swimming, but can't have my back arched at all. The problem is now in the Facet Joints. I have tried cortisone shots, epidurals, trigger point therapy, and everything else you can think of. My best treatment has been an Upper Cervical Chiropractor. If there is one in your area, it is certainly worth a try.
www.nucca.org
The facet joints are the ones on the side of the vertibrae that give you motion. Since I had the disc totally removed, and no fusion, it seems that the two joints now lock together when they get bent out of shape

Causes excrutiating pain, but sending everything in the area into spasams.
Hope you can find someway to help yourself.