#1
So I dug up my old Epiphone SG G-310 and decided to get it back into playing mode. I threw new strings on it and cleaned it up and it worked like it did before, however I've been having problems with the High E and B strings. When i play notes on the two strings up to about the 10th or 12th fret they seem fine, but as I pass the 12th fret the notes don't seem to come in as clear. I'm assuming that the string is touching one of the frets ahead of it before the vibration can get to the actual note i'm playing.

http://i1218.photobucket.com/albums/dd420/MWright1998/photo_zps4ba720a8.jpg?t=1378093490

As you can see in the picture the E and B strings are lower than the others. Is this why I'm having difficulties? If so, how can I fix this? I tried turning the little screws under the two strings but that didn't seem to do the trick.
#2
Your action may be a little low, try raising the bridge a little using the thumb wheel on the bridge post next to the high e
#3
Those screws under the strings move the saddles back and forth to adjust intonation. They won't affect string height.
Everything I say can be fully substantiated by my own opinion
#4
If it's been in storage for ages the temperature changes could have just messed with the neck relief.

Bring it to a tech.