I have no doubt John was in a tribulation. Nero was feeding Christians to lions for entertainment. He tried to boil John alive in oil.
Are you suggesting John was Exiled to Patmos by NERO?
I agree!
However this is not a reference to the great tribulation that has not been since the beginning of the world, nor shall ever be.
Aside from there being no equal to the level of devastation millions of Messiah-rejecting Jews endured as they were violently excommunicated out of covenant with God (Matt 21:40-45; Acts 3:22-24), and due to the covenantal significance of the event, that Day of the Lord's vengeance (cf. Luke 21:20-22; Isa 61:2; Jer 46:10) can never be repeated, You apparantly overlook the common Old Testament figure of speech Jesus is utilizing in Matthew 24:21: "ever was/nor ever shall be."
Scripture tells us in 1 Kings 3:12 that there was "no king like Solomon before or after him." Such statements are then repeated in 2 Kings 18:5-6 of Hezekiah and in 2 Kings 23:25 of Josiah. Obviously, they can't all be the greatest King there ever was nor ever shall be. (And, of course, Jesus Christ surpasses even Solomon -- Matt. 12:42). Furthermore, this same Old Testament idea of "never will be again" is employed of various judgments that have already been fulfilled such as locusts in Egypt (Ex. 10:12-15; cf. Joel 1:1-4), a cry in Egypt (Ex. 11:6), and judgment upon O.T. Israel (Ez. 5:9; Joel 2:2).
The Ezekiel 5:9 passage is especially instructive to us, for it states that the Babylonian conquest of Israel (sixth-century BC) would be the greatest judgment God had ever brought upon a nation, past or future. Therefore, we recognize that the expression "ever was/nor ever shall be" is a common Hebraic idiom meaning "very great" or "very much." Our Lord was simply saying in Matthew 24:21 that there would be very great tribulation. St. Luke's account of this great tribulation reads as follows:
These are the days of vengeance, that all things which are written may be fulfilled. Woe to those who are pregnant and to those who are nursing babies in those days! For there will be great distress in the land and wrath upon this people. (Luke 21:22-23)
Without question, Jesus promised his apostles that they would live to see Israel's great tribulation ("great distress in the land and wrath upon this people") and all those things come to pass in their generation (Matt 24:33-34; Luke 21:31-32).