Recommend a Back Brace?

Can anyone recommend a back brace or help me figure out what features to look for? I have chronic back problems that are sometimes OK when I’m really on my program (walking, yoga, massage), but it can get really bad at times.

I do lift weights and work on various cardio equipment (most notably of late, the elliptical), so something that would be as comfortable as possible with those activities would be great. I don’t want my muscles to atrophy-maybe that’s a silly concern. I wouldn’t wear it all the time, just during activities that would make me prone to injury.

Cautious types, I am consulting my doctor and getting and MRI, but I am more interested in pain management for now. Oh, and I’m a female if that makes any difference.

Any thoughts?