Hello dear For improving concentration try doing meditation daily. Also try to sit and study by assigning the time limit to it so that you have that in mind that you cant get up before that time limit. Try avoiding all kinds of distractions such as mobile, tv etc by restraining yourself from them.Another technique that you can use it setting up daily targets and motivate yourself to achieve them. Slowly and gradually your concentration might increase.

This may be the manifestation of Attention Deficit Hyperkinetic Disorder. You should consult a Psychiatrist for proper diagnosis and treatment. Please remember to be accompanied by a person who knows you from childhood (most likely your parents) when consulting, as proper diagnosis and treatment is heavily dependent on the information available.