'Burden' in the Bible

I applied my heart to seek and to search out by wisdom concerning all that is done under the sky. It is a heavy burden that God has given to the sons of men to be afflicted with.

I have seen the burden which God has given to the sons of men to be afflicted with.

yes, they shall be afraid of heights, and terrors will be in the way; and the almond tree shall blossom, and the grasshopper shall be a burden, and desire shall fail; because man goes to his everlasting home, and the mourners go about the streets: