Don't you find it a bit strange they all have their turns to have flashbacks, and also that it's pretty strange they all have their turns to think back to their past, then in the next episodes they're juts living life normally again? Also in the flashbacks, are they actually remembering the events - everything that happens? I know it fits in with the programme, but it seems a bit odd their memories peel back in sections, before reaching a climax.

no i dont think its the losties actually remembering events from their lives, i think its just liek were going into their minds and were seeing parts of what happened before!

I'm not so sure on this one. There have been times when the end of a flashback has seen a character have to 'snap out' of their thoughts. There are also many times where something happening to them on the island parallels incidents in their pasts. For example when Locke tells Michael that Walt is 'different' there is a flashback of Walt's Stepdad saying the same thing.

IMO, the Losties are more or less constantly tormented by their past. Each episode just concentrates on one particular lostie according to where the action will take us. i.e. Shannon was going to die in one episode so we see more of her past.
It seems that a lostie (poor Shannon excepted) is 'back to normal' the next week. However, I think they're still in the same frame of mind, remembering things frequently. Only that the writer is focusing dramatically on another lostie. It's natural for all of them to be thinking about their recent past, if they've only been around 48 days on the island.