Jeanerette, Sometimes this will happen if one of the vanes has been turned out of line from the others, so first make sure they are all facing the same angle, and free to rotate. If one is out of whack, grab the tongue the vane hangs from and carefully, but firmly, return it to the same position as the others. (As you do so it will make that same "click-click" sound)
If there's no problem with the vanes, then the chain is out of place, and will need to be put back into it's correct place. Sometimes you can readily do this from the top of the track; others the top is closed off and some disassembly is required.