'Struggle' in the Bible

When a man dies, will he come back to life?If so, I would wait all the days of my struggleuntil my relief comes.

Our lives last seventy yearsor, if we are strong, eighty years.Even the best of them are struggle and sorrow;indeed, they pass quickly and we fly away.

The Lord’s blessing enriches,and struggle adds nothing to it.

Enjoy life with the wife you love all the days of your fleeting life, which has been given to you under the sun, all your fleeting days. For that is your portion in life and in your struggle under the sun.

Why did I come out of the wombto see only struggle and sorrow,to end my life in shame?