I Am Shy

It's funny how people always come up to me and say: why do you talk so little? We barely hear your voice...and I'm like: Mhm... I don't know how/ when this really stared I didn't use to be shy when I was kid... Maybe that changed when I got to middle school idk...it was a hard time for me at school maybe that changed something inside me...Idk if i'm really shy, like sometimes I talk to stranger people so naturally and confidently on the other hand when I try to make friends it's so difficult...Maybe I'm afraid of getting attached to someone, because all the people I've met before somehow hurt me...Is that why I'm shy nowadays? Or am I just scared to trust someone?