Randomly the game freezes, and then unfreezes. It repeats until you save and quit the world.

I play a world on minecraft, and it goes fine, until it freezes and then it unfreezes. It repeats the freezing and unfreezing over, and over again making the game impossible to play. Buttons take like 10 seconds to function, even when it saves it lags it!. I actually think this is caused by either too many files on my computer or something is glitched in the game. Before i made this report, i was playing minecraft, then i found a shipwreck. I went to it, and went to the bottom room of the ship. There was a chest, i clicked it and the game did the freezing again. This time however it lagged the saving completely and i was stuck on the screen. It was so bad that i had to force stop it with Task Manager. Does anybody knows what this is and how to fix it? I really need this to be fixed!