Like Superhuman said, I would try a quarter turn on truss rod. It's possible if a small adjustment to truss rod doesn't help that your guitar wasn't made to proper scale/put together correctly. This can sometimes happen with cheaper guitars. Also, check the saddle where the string crosses over it. There may be a groove or sharp edge preventing your string from intonating correctly. If all else fails, take it to a good luthier/repair person. They can probably fix fairly easily and cheaply.