Probabilities of having some past bitter experiences where people could have snubbed you, made fun of you etc. That should not stop you from working on your limitations. In personal and professional life we will have to deal with people around us on day-to-day basis. It is not worth living with fear and/or avoiding people. Boost your self-esteem,  confident and work on communication skills. One of the tips to boost your communication - look for Toastmasters International chapter in your city and join them where you can sharpen your communication skills and public speaking.