Aches and Pains

My biggest complaint is back pain, holy cow it's killer. And the strangest thing about the whole thing is it comes and goes with no explanation. I have mentioned it at the doctors and they just keep saying it is due to the weight of the babies. It's just nerve wracking because it's a symptom of pre-term labor. So they said as long as it goes away if I lay down or rest then I am good to go. I had it in the beginning of the pregnancy when I started to really show and I have it now again when I'm even bigger. I am also having the strangest pain that goes straight up my "area". It's weird, and I'm not sure if its stretching pains or something more serious. I called my OB regarding it last week and the nurse told me it was ligaments stretching, but to me its a sharper pain, not a sore stretching pain. This is another disappearing symptom. Went away after I called and not even a week later its back...full blown! So I am going to make another phone call today before the Thanksgiving break.