1)
How was the Tzadik's heart stricken?
1.
Rashi: When he hears the predicted evil, he is pained and his heart is stricken. Radak ? Hach'os is like "v'Nich'e Levav" (Tehilim 109:16).
2)
Why does it say "va'Ani Lo Hich'avtiv"?
1.
Radak: You pained him via words in My name. This was Sheker ? I did not say them!
3)
How did they strengthen the Rasha?
1.
Radak: They told him that he will live.
4)
Why does it say "mi'Darko ha'Ra" (masculine)?
1.
Radak: Sometimes Derech is masculine, e.g. "Zeh ha'Derech Lechu Vo" (Yeshayah 30:21).