In 2 Chronicles 7, the Lord simply reminds Solomon of the previous agreement. If Israel obeys, they will be blessed. If they disobey, they will be judged. The judgment is meant to bring Israel to repentance, and God assures Solomon that, if they will be humble, pray, and repent, then God will deliver them from the judgment.
As it was back in the ancient of days so it is today. We need our nation to recognize that this bilateral covenant promise requires that we all do so en masse (as a whole).
The Israel nation as a whole (en masse) repented. However and obviously, not every single Israelite repented and prayed, but it was national repentance. There was never any indication that a small minority of the nation (a righteous remnant) could repent and pray and that the fate of the entire nation would change. God promised deliverance when the entire nation repented.
With that said, it is never wrong to confess our sins and pray—in fact, it is our duty as believers to continuously confess and forsake our sins so that they will not hinder us (Hebrews 12:1) and to pray for our nation and those in authority (1 Timothy 2:1–2).
We are in need of National repentance and we need all hands on deck! God will heal our land, but not until we as a whole (en masse) humble ourselves, repent and turn from our wicked ways!