Hi B.,
While reading your post, I was wondering What she is lacking in comfort or a secure feeling?
Who watches her when you are working? I would start looking there first, as I have not heard of this in a child so young.
Maybe if you could hold her an stroke her hair for her, and hold her little hand as she reaches for her hair, This may soothe her and bring a sense of security, that mommy is here now, and she is ok,Talk to her , or even play soft music
Maybe she is left to cry alone to fall sleep,at the day care or sitters.
Does she have a snuggly bear or something to hold onto as she goes to sleep.
It really sounds to me as though she is expressing her frustration,or fears, the only way she knows how. Does she cry when left at the sitters?
I had a bad sitter once, and through watching my child's reactions about going there, I changed sitters, and she was eager to go to the new one.I never found out what it was, but she was happier , and so was I.
Just a suggestion, But I would really be concerned for my child.Did you have to return to work soon after her birth?
My very best wishes for you both.