If there is inflammation present, then ice may very well be prescribed. It's been my understanding that most lower back pain does not involve inflammation and therefore does not require ice. If your experts are telling you to ice it, then it very well be warranted in your case. In general, tho', heat is usually prescribed for back pain from what I've been told and from what I've read.
Every tool is a weapon -- if you hold it right. (~Ani DiFranco)