Yes, they just seem to reappear and often in the same place. I saw on Kellymom that taking lecithin may help, so I am going to try that. If anyone has anything else to offer or just to let me know that lecithin works, I'm all ears.
Try nursing in different positions each time, and when a plug happens, nurse in a position such that baby's chin is pointed towards the clog. Also try doing breast compressions while nursing, and rubbing or heating the area that usually clogs before/during nursing.
I remember someone saying that when they stopped taking lecithin, they had more plugged ducts, so I would definitely give that a try.