Rich: If it was "one" door, I would say, "Ok, let's check the to see if this door is still screwed in and not just saggin'...."! Considering it is more than one, you probably have settlement problems. This may not end up being a huge problem, in the final analysis.
All this could, for example, be caused by one pier or what ever in the middle of you structure. Fix that one puppy and you are done. This all sounds really good since there is no evidence of cracking.
On the other hand, my friend, not knowing age or configuration of your home,or how it is structured, this may be the beginning of your house sliding down the hill to hole #3, dog leg left.
Don't get worked up. Get a contractor over and have him look things over. Make sure he is a good one. You could end up spending a lot of good money after bad if you don't.
Remember, post back up and let us know what the real issues are when you find out. There are good people on here that can assist you further.