Steering wheel controls.

Toyota warns about holding their steering wheel located buttons down too hard, or too long. I would guess the switch is damaged and needs to be replaced. You could try tapping it hard with the base of your thumb, but I wouldn't recommend it. If you take it in, they will pull off the cover during the replacement process and will be able to see if the wiring is okay as well.

Most likely clockspring. It services the steering wheel airbag, audio controls, and horn as well, so any problems with those systems would further suggest that the clockspring is the problem. Replacement is pretty straight forward but does involve the airbag system, so if you aren't comfortable with that, bring it to a shop.