I know the question is a little vague. But if somebody was making up problems to gain attention and some sort of affection from others then what could be causing them to act like so? Maybe you think they had a rough childhood. But what if they were acting like that when they was young as 8 or 9 with no real reason to act that way? I’m talking about stories like being abused or being pregnant… lies as serious as that just to gain some sort of attention. What could be the cause?
This person probably doesn't feel as though their life is interesting. These are lies that usually a compulsive liar would tell. They are also examples of pathological lies. This person probably has grown up feeling like less than important, and is making up stories to get attention and to feel as though they are important and interesting. It's very common, and unfortunate.
I had a friend like that in middle school - I would imagine that it might have something to do with a need for attention. Lack of attention from family members at home, maybe because of a large family, maybe because of both parents work long hours, or one has been absent, so the other must work long hours? I think that could be a possible cause.