Hey, There might be several activities, which you can concentrate & carry on for how much ever time you like. If it is so, you should not have any issue with your health. If it is not so, you should get a general health checkup done. Coming to studies, what you are studying need not be something which seems interesting, practical, meaningful or engaging to you and hence might create boredom which is getting expressed in one or the other way. You would notice the absence of boredom if there is a valid deadline like exam in the vicinity. From today, make it a point to know your reason for studying a subject or a chapter before you start with it. Understand how a particular subject is relevant and how can you practically apply it. Begin by reading the overview and thinking about the relevance and meaning of same followed by reading the chapter. As you read, keep making notes of what you have understood. When you start studying keep a reachable target and do not stop unless you make it. Have a deadline to study continuously for 20 minutes tomorrow and increase it eventually. Take a break after every 30-45 mins if you find it hard to continue however if there is a flow, do not break the flow. If this doesn't help consult a psychologist/counselor so that he/she can help you with study skills & concentration after understanding the way you are and your motivation pattern thoroughly. Happy Concentrating.