Did you buy the bike new? Some places, when you buy a new bike from them; will do a yearly 'tune up' to address those sort of issues.

I'm a newbie but I've been learning and would suggest these two videos to help you figure out what maintenance needs to be done:

https://www.youtube.com/watch?v=8LqTmvuf6tw

https://www.youtube.com/watch?v=Bbk5RcH0bbQ