He is rebuked with pain on his bed, and with constant pain in his bones.
on his bed he is punished. Job 5:17, Job 5:18; Deu 8:5; Ps 94:12; Ps 119:67, Ps 119:71; Isaiah 27:9; 1Co 11:32; Rev 3:19.
with strong pain. Job 7:4; Job 20:11; Job 30:17; 2Ch 16:10, 2Ch 16:12; Ps 38:1-8; Isaiah 37:12, Isaiah 37:13.
Source: The Treasury of Biblical Knowledge
Job had lamented that his suffering was undeserved. Elihu responded to this complaint by stating that he was God’s messenger, a mediator for Job to show him that God does not act capriciously, but allows suffering as a discipline to lead one to submit to Him as righteous (v. Job 33:23), and to repentance (v. Job 33:27), so that his life may be saved (vv. Job 33:24; Job 33:28; Job 33:30). God allows suffering for spiritual benefit.
Source: MacArthur Study Bible
Watch Deu 8:5; Pro 3:12.