My bones are vexed— Bones, reins, inward parts, often in scripture signify the same as heart, soul, thought; see Psalms 35:10 where bones probably signify the same as here.
Related Commentaries of Psalms 6:2
Psalms 6:2
2 Have mercy upon me, O LORD; for I am weak: O LORD, heal me; for my bones are vexed.