I underwent cataract surgery ang syringing of lacrimal duct, and now I often get small painful nodules on eye lid margins.....what to do?

Likely meibomian. Nodules are likely meibomian glands clogging. Did you see an eyeMD to see if the small nodules are little styes? Best way to help with this is to apply warm compresses/hot compresses to lid margin & use diluted tea tree oil according to directions under "lid hygiene" at eyedoc2020@blogspot.com. Best of luck.