For if our heart condemn us, God is greater than our heart, and knoweth all things (I John 3:20).
As powerful as a condemner the heart is, God is able to free the prisoner from its grip. For with God nothing shall be impossible (Luke 1:37). As strong as the heart is, the power of the Holy Spirit is greater. He empowers our spirit, which gives us stamina and fortitude. The Lord steps in and helps us overcome the overpowering affect of our conscience. So when pain makes an attempt to take our heart by force, Christ in us will prove that He is mightier!
When we have a hurting or broken heart, there is only one quick fix, a Word from the Lord. This is why it is necessary to be able to navigate your way through the Bible in a way that speaks directly to your needs. A topical book, also, is helpful.
If you are experiencing misery in your heart, remember how David regained his. Ask God to strengthen your heart. Keep in mind that you must do your part: Be of good courage, and he shall strengthen your heart, all ye that hope in the LORD (Ps 31:24)