Sexual Signs

Hey. I've been thinking (even though I'm still single) if your boyfriend kisses your neck, shoulder or squeezes/touches your butt, does that mean he's giving you a sign that he wants to have sex with you? And from seeing "50 Shades Of Grey", seeing him grab the girl's thigh, meaning he wanted something sexual with her or something. Can you clarify on this please? I'm very new to the sex topic particularly as I'm not comfortable at all with talking about it.