Well, there is a difference between muscle soreness from usage and actual injury. DOMS is just a muscle soreness that effects most of the muscle of a given body part (and can be kinda painful at times). Injury on the other hand has pain, but many times (not always) effects joints/tendons/ligaments and can be a much sharper movement style pain. I have had DOMS in my hams bad enough at times, where it is quite hard to navigate stairs or bend over to pick up a pencil.
This is another reason for recovery W/O's. (lighter moves, say squats, BP's rows etc. where you just get some extra blood flow into the areas, but not using any kind of heavy working weight. Like a flushing workout. It can help to alleviate DOMS to some degree.