1)
What are "Rosh Homiyos"?
1.
Rashi: In a place where it is heard. It announces and says the matter below - "Ad Masai Pesayim
2)
Why does it say "Tikra"?
1.
Malbim: This is more than making the voice heard. He intends for the people to whom he calls; Nesinas Kol is for the Klal. A Navi or one who expounds will stand in front of a multitude.
3)
What are "Pischei She'arim"?
1.
Rashi: It is where Zekenim [Malbim - and judges] sit.