#1
Howdy, first post here.

I play an Epiphone Les Paul and here recently my high e string buzzes on the fret bar on the 15th fret. Any suggestions on why it would do that?

Probably a simple answer.
#2
There could be a couple of reasons for this. Most likely you probably just need a setup. This involves taking your guitar into a tech where he can set the tension of the truss rod in the neck and the action (height off of the fretboard) of your strings.

Another alternative, which is still minor, is that you may have a slightly raised fret at the 15, hence the buzz. This is also a fairly simple fix for any guitar tech. I hope this helps.
Satan. Grant this man the gift of revenge against his foes at the Food Network.