What Causes Pain And Strain In Eyes While Having Myopia?

My eyes hurt almost everyday. They feel strained almost all the time. I use glasses and I dont know if thats the problem. I also feel as if I need a stronger prescription because I cant see from far at times, but I fell that the stronger prescription will make my eyes hurt more. I have myopia (I think thats how its spelled), if that has anything to do wih this. please answer with any advice or suggestions on what to do or what I have. Thanks.