You're confused. A lot of people think astigmatism is having a rugby shaped eyeball. But the most common cause of astigmatism is from having dents in the cornea part of the eye. Excessive reading has been found in research to be one of the main causes of this kind of astigmatism
Source:
http://www.foxnews.com/story/0,2933,225983,00.html
You see while reading your eyeball doesn't move as much and blinking become less frequent. The upper eyelid always places pressure on the eyeball. If that pressure is left for too long then you will end up with dents or more correctly 'depressions' on the surface of the cornea. To see an example of what I mean click this link:
http://www.google.com/images?q=corneal+topography&um=1&ie=UTF-8&source=og&sa=N&hl=en&tab=wi
A normal cornea shows up in green colour. Unusual flatness or steepness is shown by red and blue colours.
There are other ways to get astigmatism. Some people are born with oval shaped corneas. Another possibility is having a flaw in the curvature of the internal lens.
You didn't say your age. If you're around an age like 20. Then the likeliest cause of your hyperopia is eyeball shortening from the front to back. If you're older than that then the cause is likely to be prebyopia (old man's eyes). The latter is irreversible hence the reason many elderly people use reading glasses.
Reading glasses have never been proven to improve near vision. Neither have they been proven to maintain the current quality of the person's near vision.
I have used reading glasses myself for a year. I didn't take them off all day. They don't give headaches for me but I did find that I stared at people a lot more and I also became detached from society. I picked that up from from differently I act now without the glasses.