How do you get through to a scorpio ? (10 points)?

i am involved with a scorpio girl and she seems very upset about something and i have tried talking to her about it but everytime i do she just completely shuts down and wont respond or talk abut her feelings at all, and even denies being upset but its very obvious something is bothering her,she is not the same lately, i am going nuts, i love her and want to help but she is not making things easy, so my question is,why are scorpios so closed off and difficult and how can i get her to open up to me?