1997 Plymouth Voyager Door Lock/Latch

The driver's door seems to not be closing properly. There is a "give" to it if/when I "bump" against it. Also, when driving, the door ajar alarm chimes, the interior lights flash, and the locks engage. It varies on how often this happens, mostly around turns, on rough patches, and it can be caused "on purpose" by bumping against the door. What I need to know is if it is a physical, mechanical problem, like a latch or part that can be personally replaced or if it is most likely a computer/electrical problem that needs a professional.