There are two simple steps that can prevent this from happening. First, change the flapper in the tank. The flapper is only a couple dollars at Home Depot, Lowes, and maybe even Wal-Mart. It is an easy fix and only takes a few minutes. The flapper keeps the toilet from constantly running. Not from adding water into the toilet bowl but the running of the water. Make sense?
The second step, the messy step, is cleaning this piece:
Notice the black circular thingy with blue stuff on it? (Don’t you love my choice of words?) That piece is what got stuck. The gray piece had so much build-up on it that the black piece could not move. I took a Brillo pad and scrubbed all the build-up off that piece (hence the blue stuff on the black thingy). Thank you to my step-dad for the advice. The black piece now moves freely up and down as it should. This step is messy; as you can see the sides of the tank have muck on it from me moving my hand around the piece.