Here "hand" refers to Yahweh. The entire phrase is an idiom that means "you afflicted me." AT: "you made me suffer greatly" (See: [[rc://en/ta/man/translate/figs-synecdoche]] and [[rc://en/ta/man/translate/figs-idiom]])
This may be a musical term that tells people how to sing or play their instruments here. Some translations write the Hebrew word, and some translations do not include it. See how you translated this in [Psalms 3:2](../003/001.md). (See: [[rc://en/ta/man/translate/translate-transliterate]])