IPhone 4S volume white box not showing up?

Every time I use the + and - to lower or rise up the volume usually the white box shows up and now it's not help please I must no is it the Assistive touch my lock screen button doesn't work so I'm using the assistive touch did I press something by accident and maybe that's why the white volume boxes is not showing?

Clean the bottom of your iPhone with a q-tip and a toothpick. Dirt and lint gets trapped in the dock port making the iPhone think its connected to a docking station with external speakers.