Do i have ADD? or can i help this on my own?!

i know i have a problem focussing at school sometimes and when doing homework at home. I really cant focus at home at all and would like some medicine to help me with with the problem. I can focus on things that i enjoy doing and not things like most young adults movies, tv, video games,etc... I love to work and study and read on my own time about philosophy, world religions, ethics, and other things of that nature but i sometimes have a hard time focusing when i am trying to work on my own for school. Do i have a problem and do i need add medicine a low dose?