My sister claims to have a neurological disorder that's causing a "debilitating twitch" and I'm not buying it. Am I out of line?

Some background: My sister has always been a little neurotic, but nothing too extreme. She was diagnosed with OCD as a teenager, but from what I could tell, it was fairly minor and was never medicated. She's also a bit of a hypochondriac. None of this has ever affected how she functioned socially or professionally. She graduated from an ivy league school and has a great job (and relatively low pressure) at one of the premier corporations in the world. She is naturally intelligent and extremely competent.

However, over the last year or so, she claims to have developed a twitch that she says is destroying her life. She says it keeps her from sleeping at night and that she's developed insomnia because of it. Apparently, restful nights are few and far between for her and it is absolutely destroying her quality of life. She needs the absolute perfect conditions in order to sleep, so you can imagine how difficult it is to stay anywhere with her. Last time I stayed in a hotel room, she literally kicked and screamed until my Mother (who essentially always heeds my sister's ridiculous requests) agreed to change rooms. My sister was 24 years old at the time. But I digress. I guess I'm also taking this opportunity to vent a little bit.

Anyway, I've had multiple conversations with her about this problem and I have come up with the following conclusion: she is mostly full of shit. I don't believe she is lying about the twitching, but I think that she is blowing it way out of proportion. It seems to me that it is kind of a vicious cycle. My theory: She was really exhausted one week and a few of her muscles started twitching due to stress and lack of sleep. This worried her (because of her hypochondria) and it started to occupy her mind more and more and she started losing sleep. The lack of sleep perpetuated the twitching and the cycle started all over again. She claims that she has a neurological condition, but has never been diagnosed with anything, even after seeing a neurologist. It seems to me to mostly be a cry for attention that has gone a little too far. Family visits have become almost impossible and I hate that. I refuse to feel sorry for her, but I feel kind of like a dick for it. What gets me most angry about the situation is that she can't seem to focus on the numerous positives in her life. Rather, she chooses to dwell on this twitching, meanwhile taking everything else in her life for granted. It seems as though she is approaching the entire situation like an adolescent girl. "No one will ever understand how hard this is." Actual quote. Then I asked her if she actually thinks her life is harder than someone dying of starvation in a third world country. She said yes. Disgusting. I honestly don't know if I can talk to her anymore.

So, reddit, I'm turning to you for some words of wisdom. Am I out of line? Do you think she actually has some incurable disease as she claims? Any light you guys can shed on the situation would be greatly appreciated. More details can be provided if you want.