Rambley McRambles strikes again

Something I'd really like to figure out is why I find it so hard to be affectionate. My mom tells me that when I was a baby I didn't mind being held, but when I was done I was done and would let the holder know that. Affection was ok in small doses. I'm still that way...I find it hard to verbalize my feelings for people and especially to touch them. I may feel so intensely about a person but find it incredibly hard to say that. I have a hard time saying "I love you" to anyone, even my family whom I love more than anything in the world. I have a hard time letting someone give that first kiss. Hugs are the one exception to my tendencies. It's not that I don't want to be touched, so I don't understand why I am so afraid or hesitant or nervous about it. The exception as far as what I say is when I write it...I can write anything to someone as long as I don't have to watch them read it. Something about immediate reactions freaks me out. Also, when people are upset, I know I should hug them and say comforting things, but I always just stand there and wish I wouldn't have such a hard time reaching out to them. On the complete flip side, once in a relationship I am very affectionate and have no problem at all being that way. Why can I do that but not say "I love you" to my mom and hug a grieving person?