An intriguing point about the Hebrew word qe’ver is that it can refer to either a singular grave, or to many graves. But the Hebrew word she’ohl’ always has to be singular. There is only one she’ohl’, but while there can be one individual qe’ver, there can also be many of them. Finding out why there is only ever one she’ohl’ is revealing as to explaining the difference in meaning between the two words, and what they speak of. They do not mean the same thing although the words you mention seem to be interchangeable in many places in the Hebrew scriptures. In the following quote, note why it is admitted that qe’ver can be used as parallel to she’ohl’, but it is not equivalent to she’ohl’:
"The Hebrew word qe'ver is the common word used to designate a burial
place, a grave, or a graveyard. (Ge 23:7-9; Jer 8:1; 26:23) The
related word qevurah' similarly may refer to an earthen grave or to a
tomb excavated in rock. - Ge 35:20; 1 Sa 10:2 In Greek the common
word for grave is ta'phos (Mt 28:1), and the verb form (tha'pto) means
'bury'. (Mt 8:21,22)... Since these Hebrew and Greek words refer to
an individual burial place or grave site, they are often used in the
plural as referring to many such graves. They are, therefore, distinct
from the Hebrew she'ohl' and its Greek equivalent hai'des...
Nevertheless, since one's entry into Sheol is represented as taking
place through burial in an individual grave or at a burial site, words
pertaining to such places of interment are used as parallel though not
equivalent terms with Sheol." (Insight On The Scriptures Vol. 1 pages
994-5 Watchtower Bible & Tract Society, 1988)
One way of expressing this unequivalent parallelism would be to say that the grave was the entry point into she'ohl' so that the two are bound together, yet distinct. That, basically, is why different translations of the Hebrew scriptures at Isaiah 5:14 say either ‘place of the dead’ or ‘the grave’. Saying ‘hell’ can be a bit misleading, however.
“There is no English word that conveys the precise sense of the Hebrew
word she'ohl'. Commenting on the use of the word ‘hell’ in Bible
translation, Collier’s Encyclopedia (1986, Vol. 12, p. 28) says,
“Since Sheol in Old Testament times referred simply to the abode of
the dead and suggested no moral distinctions, the word ‘hell’, as
understood today, is not a happy translation.” More recent versions
transliterate the word into English as “Sheol”. – RS, AT, NW.
(Insight On The Scriptures Vol. 2 page 992 Watchtower Bible & Tract
Sheol is never used in the plural but 'graves' can be plural and singular. Qe’ber is used in the plural 29 times.
Sheol is never used to say bodies go there - not even bones - but they body goes to qe’ber 37 times.
Sheol is never said to be near the surface of the ground, as is a grave, but qe’ber is located on or near the face of the earth 32 times.
Sheol is never used as in this made-up sentence "There is Joseph's grave." But that's just how qe’ber is used, 44 times.
Sheol is never used about a dead person being put in, or laid in it. But a dead body is put in the qe’ber 33 times (1 Kings 13:30).
Sheol is never described as being dug, as is a grave. But qe’ber is used that way 6 times (Gen. 50:5)
The OT speaks of the place where dead, material bodies are put, and that is qe’ber.
The OT speaks of the place where the immaterial part of those dead people go, and that is she'ohl'.
Beyond the grave lies Sheol but there’s no short-circuiting the way into Sheol – the body has to die.
A translation of Isaiah 5:14 that says ‘Sheol’ is not at odds with another that says ‘grave’, given a possible root word for she'ohl' being the verb sha.’al’, meaning ‘ask: request’, providing the thought of an insatiability to the grave, that it’s never satisfied, always seeking more. One can picture the grave as an opening, black mouth, swallowing corpses that disappear down into the depth of Sheol, or hell (if that should be the ‘compartment’ of hell that the immaterial part of the deceased is allocated.) Bear in mind that some Jewish rabbinic schools taught that Sheol had two sections, with an uncrossable chasm between them, one a place of torment, the other a place of bliss (known as ‘The Bosom of Abraham’.) Consider Jesus’ words about the rich man dying and finding himself in torments, as opposed to Lazarus who died and found himself in bliss in ‘The Bosom of Abraham.’ Jesus also mentioned that huge chasm – see Luke 16:19-31.
"The Life And Times of Jesus The Messiah" by Alfred Edersheim (1971) Appendix XIX, On Eternal Punishment, according to the Rabbis and the New Testament" (see vol. II Book V ch. vi) http://www.ccel.org/ccel/e
"Josephus' Discourse to the Greeks Concerning Hades" as in "The Works of Josephus" translated by William Whiston, 1980, page 637 http://www.ccel.org/search/fulltext/Josephus%27%20Discourse%20to%20the%20Greeks%20Concerning%20Hades