do dreams tell the future?

Properly interpreted dreams can seem to give a glimpse into the future. But for the most part prophetic dreams are about global events. It could be that you miss the closeness that you shared so you are regressing to place where you were happier. Or there could be some type of prophecy in there. Remember dreams are almost always symbolic and not literal, so look for other meaning beside the obvious one.

they can predict about what's going to happen the following day if and when they interpreted correctly.
as for dreaming of your ex boyfriend, im not really sure what that could mean.

Simple answer. No.

If your dreaming about something like that its only because you are missing him or something like that.
If you want to get all nerdy with it then i'd have something to do with your subconscious mind.