Action and string tension is determined by the factors mentioned by the fellows above. String gauge, neck bow, saddle height, scale length of the instrument...maybe a thing or two I'm forgetting to mention.
I'd suggest bringing your guitar to a tech, explain your situation, and he can get you all hooked up. It'll cost the price of a new set of strings and whatever the tech charges for a setup. Around here it costs me about $25 plus strings. it could cost more if he has to do something out of the ordinary like file the nut slots or replace some parts. If your instrument is properly adjusted, you'll enjoy playing it so much more.
If it's all set up well and you're still having trouble, then it ! may be time to look for a shorter scale instrument or a nylon string guitar.