Michelle, hey..a psychcologist will give you constructive tools to overcome any social problem that affects your mental health. Like goal setting for example is an important step to mental health, because it keeps you in control of your life and lets you steer yourself to those activities you find fulfilling. Talk therapy is helpful, as well, because it lets you express emotions that you were keeping inside or work out situations that you were not aware of before therapy.
It is helpful, and I think everyone can benefit from it. Social people get alot of this kind of feedback from their friends and from their social support. Although they may receive information which isn't constructive or helpful for their mental health.
Please do not think that I am saying shyness is a big mental health problem because for some it isn't. If you are comfortable with the amount of social interaction you have and function the way you want in social settings, a therapist is not needed for you shyness. If you suffer from depression which is always a mental health issue or want to be more social and not being so affects your day to day life...therapy may work!!
Two things, a pyschologist may be expensive. Mine turned to about $20 a session through my Health coverage (pretty cheap but with my budget...expensive). Another, you may feel afraid about seeking help. Just remember, everybody needs someones help. If you don't have a positive group of people you can rely on to help change a negative mental issue than a mental health professional is the way to go...