Lower back question?

Occasionally I get these raised areas on my lower back, usually along the spine. They kind of itch, but feel like a bruise when touched...its not directly on the spine, just right next to it on either side. I'm not in pain unless I press on the area. I plan on going to the Dr., I just wanted to see if anyone else has experienced this kinda thing or knows wtf is causing it.

Thanks :)