Will's and Kendall's advice is good. The truss rod is there to straighten the neck; that generally has the effect of lowering the action, but if the neck is already straight enough (there should be a little bow, or "relief"; how much is a matter of personal preference), it's best to leave it alone, and focus your attentions elsewhere. That generally means looking at the bridge saddle to see if its height needs adjusting, before looking into more invasive procedures matters (fret work, neck reset, etc.). But it needs to be looked at by someone who knows to be diagnosed properly (in other words, advice on an internet forum will only take you so far). Good luck.