This psalm describes  David's struggle with unconfessed sin and then the joys of forgiveness when he humbled himself before God.
1. The burden of sin- 32:3-5
His bones have wasted away and he is groaning- 32:3
His pain is perpetual- 32:3 "all day long" and 32:4 "Day and night"
The hand of the LORD is heavy against him- Ruth 1:13; I Sam. 5:6, 7, 9. The hand of the LORD that David looked to in 31:5, 15 is now pressing against him heavily. This is not God's fault but it is David.
His strength is dried up- 32:4
Are you carrying this heavy burden?

2. The blessings of forgiveness- 32:1-2
Three different terms for evil are used- transgression, sin, and iniquity
Three different terms for forgiveness are used- forgiven, covered, not imputed or not counted
Three different terms for confession are used- acknowledged, did not hide, confessed
God is more willing to forgiven than we are to confess- 32:5

3. The mood changes at 32:6 and he calls on all to learn the lesson from this.
pray to God in a day when He may be found- 32:6
Do not be like the horse who has to be beaten to be kept on the right path- 32:9
Contrast the wicked- 32:10- and the righteous- 32:11. The righteous rejoice at God's salvation.