Today, the 14th of Iyar is Pesach Sheni. According to many opinions one does not fast on this day, make Hespedim, or a Hakomas Matzeivah. Piskei Tshuvos 492:1
There are different minhagim regarding the saying of Tachnun, (El Erech Apayim), and Lamenatzeach on Pesach Sheni (as the Shulchan Aruch does not mention to omit these tefillos). Many have the minhag to eat Matzah on Pesach Sheni by day, zecher L’korbon Pesach. Piskei Tshuvos 492:1, see also Shaarei Tshuva @ SA 131:19
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In the sefer The Jewish Calendar,by Rabbi David Feinstein on p.98 he writes:” Some have the custom of eating matzah this day ,while others do so on the following night.”
And the Rebbes of the kretchniff dynasty have a minhag to make pesach sheini seder.