Learning problems.i'm in college, and when the lecturer explains something,i hear but i can't process information.i understand myself,then forget.why?

Doctor can evaluate: There are many reasons a person may feel he does not remember the things he hears in the classroom. Such a person can write down his symptoms, to tell his primary care doctor (or his pediatrician if that doctor will still see him as a college student), but start by describing any symptoms in middle school, and in high school. Also, any and all mental health issues and stressors become important.