Why are some keys on my keyboard, volume bar, and other touchscree features not woking right?

[AC Question]

It takes a lot of effort and the predictive text feature to type this legibly. Without tapping on a key three dozen types, my nomal typing stats to look lik itxds missing a f ltts. You see? Not only that, but when I try to use touchscreen to turn the volume up or down! it won't move when it's turned quieter, but can work when the volume is high. The keys that act strange are on the left, but buttons like 'a' 'q' 'z' and 'x' work. Other one's won't work or will press others buttons.
My device is a galaxy tab 3 311 I think .

 

[B. Diddy]

Welcome to Android Central! Do the same keys give you problems when the keyboard is in landscape mode, compared with portrait? If not, then your touchscreen digitizer is probably faulty, or has a loose connection. Bring it to a repair shop.