Only you can answer this. Really ask yourself if it's a problem with your discipline, or a problem with your motivation. If it's a problem with discipline then

Only you can answer this. Really ask yourself if it's a problem with your discipline, or a problem with your motivation. If it's a problem with discipline then you need to figure out a strategy to improve your discipline. Pomodoro timers could help, or being mindful of distractions and minimising them. Read Atomic Habits and Deep Work if you want to dive more deeply into the nuts and bolts of this. You need to be actively engaged in minimising distractions if you want to get stuff done, otherwise our forever connected world will eat you alive. Motivation is deeper. If you don't understand what you truly want, and align yourself to that, you'll be constantly fighting yourself. Why do you think you should be studying? Is it because you genuinely want to learn more about a subject? Or do you just think you should be studying because that's what a productive person would do? Maybe spend some time journalling about this to try and wind back why you want to do this and why you think you aren't doing it. Or, maybe you just have ADHD.