I also have a foster son whom I am going through the adoption process with. He has been in foster care for five years, ans with me for one year. He also demands attention through the use of imaginary aches and pains. I found that having predictable routines in the day and week when he knows that will just be "our time" together helps him to seek attention in more appropriate ways. For example, meal times, bedtime stroies, and special "movie nights" at home. I also reinforce him when he appropriately seeks my attention. He is also in therapy for an attachment disorder due to lack of bonding with caregivers (ie parents) in his early years; which is something you may want to consider about your daughter.
Dear Cindy,
A much overdone idea in child rearing is about kids behaving in certain ways in bids for attention. But, in some instances, the idea has some merit.
If, in their early years, children don't have the benefit of adequate parenting, their need for nurturance is not fulfilled, and they can continue to act in a needy way that is inappropriate for their age. In turn, this can be off-putting to peers and others and test the patience of adults.
Relative to your interaction with your daughter, I'd be sensitive but straightforward about the matter. Your relationship will help her accept what you are saying. Her behavior in conversations and her exaggerating somatic ailments are both examples of her neediness. At her age, with some focus on this, she may well be able to control this behavior and have her needs for attention met in more acceptable ways that do not put people off.
You might also consider the involvement of a child mental health professional to help her with this, or group therapy with other teens.