keyboard buttons responding to different things
i recently updated my mac, and ever since then my keyboard hasn't been functioning properly. Whenever I click the brightness down function, the brightness goes down but the sound also goes down, and vice versa. The shift button also selects 'enter', and the down arrow key is not working altogether. The "-" used to turn the keyboard brightness down, but then I turned the function keys off and that stopped happening. I turned off the function keys and then pressed the brightness down button and when I did that the volume didn't change, but everything that doesn't involve the function keys is still happening. I've done a full restart, and shut down my laptop multiple times, and i've also reset the PRAM, but nothing has worked. What should my next step be?
MacBook Air 13", macOS 10.12