I come at it from a different angle than everyone else here. In my opinion, your problem is that you are not goal setting properly. Every time you get stuck or complete a task I suspect you browse HN.

Instead of browsing HN when you get stuck, break your task into sub-tasks until it seems actionable.

Then I imagine you browse HN when you complete a task, to eliminate this, make sure your task list has many tasks in it, this will make you aware of your workload and decrease the desire to idle.