Sounds like you're syncing with an online service, but forgot to turn off the syncing in iTunes. Don't do both. It causes a loop that will duplicate you contacts.
Everything, computer and devices, should sync to a single source. If you use iCloud then your contacts on the computer and device should sync just to iCloud, not directly to each other.
iCloud almost never causes conflicts. Conflicts are caused when the same contact is changed in two places before it can be synced to all devices or computers. In order to cause a conflict with iCloud you would need to keep either your iPad or computer off line; make changes on both, then bring the both devices back online.
Conflicts with iTunes are much likelier. All you have to do is edit the same contact on both devices in between syncs.