How could a psychologist change my social anxiety&to what extent could i change knowing that i have the desire to change but not my lifestyle ?

Cognitive Behavioral: Therapy my help you restructure the negative thoughts that lead to behavior that distresses you. See www.nami.org/Learn-More/Treatment/Psychotherapy. The extent to which it can help largely depends on your commitment to address painful past experiences & relationships in order to learn that you do not have to allow them to guide your current emotional responses & behaviors in certain situations.