I am not getting the impression so much that you don't care to have a relationship with THIS girl so much as you don't care to have a relationship PERIOD, not of any kind. Not sexual, not emotional, not friendly... nothing. You certainly have that right, but it is pretty unusual to isolate yourself so completely.
It seems like you have a greater-than-average fear of intimacy, and I think you are letting it run your life. That is why I think you should talk to a professional.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?