Is having overly sensitive legs normal?

My legs have always been incredibly sensitive. I feel uncomfortable when people touch my legs, but it's worse if they're bare. If I pop my knee or ankle or something, it hurts way worse than how most people react. I mean, my arms or anything else isn't that sensitive. Recently, I've gotten serious with my boyfriend, and when he touches my legs it almost immediately turns me on (he is very aware of this btw, and LOVES to pick on me cause of it), and it doesn't really ever hurt or bug me if he touches my legs. Even if he TALKS about touching my legs I get goose bumps, and my stomach churns. So, this is actually three questions:

1) Is it normal to have legs this sensitive?

2) Does anyone else have legs or other limps sensitive like this?

3) Is this called anything? Like a disorder or a condition or something?

4) How come I'm turned on, rather than the normal recoiling reaction, when my boyfriend touches my legs?

Thanks in advance,

Angelica <3