Scotland is suffering under Macbeth's rule. He illegally became king by murdering the previous king, Duncan. Once he started his reign, he changed completely - he used to be an honorable warrior, but his ambition corrupted him, and he became a tyrant once he assumed the throne. During his reign, people in Scotland were afraid all the time about what their new king might do, and his own country was suffering.
This is what Malcolm had to say about Macbeth's rule, which testifies to his terrible reign:
"I think our country sinks beneath the yoke.
It weeps, it bleeds, and each new day a gash
Is added to her wounds."