1)
Why did he say "Ach Rik [Zikisi Levavi]"?
1.
Rashi: This refers back to "Eichah Yada Kel" (verse 11). We guarded His Mitzvos l'Rik (in vain). We are stricken the entire day!
2.
Radak: I, Hashem's nation, I purified my heart, and even so, I have evil [afflictions] and no serenity, and they have good and serenity!
3.
Malbim: I did not have any sin in thought. However, it did not help me - refer to 73:14:1:2.
2)
What is the meaning of "va'Erchatz b'Nikayon Kapai"?
1.
Radak, Malbim: I did not have any sin in deed.
