In my game I suddenly found myself unable to break blocks using the left mouse button option, this only happens in my current world. When hand is empty or having a tool (pickaxe, axe, shovel, hoe) it cannot break down blocks, only attack.
Clicking the left button can only perform the attack option, and the right button still works perfectly.
The game is on survival mode and I have repeatedly reset the control options for mouse, even switching to touchscreen, nothing works.
Are you sure you're in survival mode and not adventure mode? In adventure mode, you have all the capabilities of a survival mode player, minus the ability to break blocks.