Girl's Behavior

Why would she all of a sudden "clamp up" the second she sees me?

Why would she react like that the second she saw me? (girl 2)

Does she likes me?

Is she shy with me?

I'm with this girl that I know for a few months, she has touche me with her body (she has almost gotten in the way fully knowing that I was there, it almost felt like she wanted me to hug her without her saying anything. Our bodies were touching). She sometimes looks at me from a distance, helps me slightly more than anyone should and she seems to talk more with others except me.

I was walking on a hallway when I hear some music from a corner of a hallway, suddenly I see (girl 1 walking while she's slightly moving to the beat). (girl 1 sees me and she seems like she didn't bother her seeing her like that) but when (girl 2) arrives, she seems to be really enjoying the music and she's dancing a little bit to it. The second she saw me she all of a sudden she stopped (like she saw someone who might've made a different reaction).

Why would she all of a sudden "clamp up" the second she sees me?
Post Opinion