Ow...OW!

I'm 17 weeks and 3 days with twins. I wake up and go throughout my day with radiating lower and sometimes upper back pain. I had some minor issues with my lower back always needing to be 'popped' before I got pregnant, but now it's just horrible, especially when I have to stand, sit, or lay down for long periods of time (for example, sleeping, the pain wakes me up.) I don't know what to do. It's making me practically lethargic and so stiff and slow! If I'm like this at only 17 weeks in I'm so scared at how much worse it can get. Is there something I can do? I mentioned this pain at my last doctors appointment last week and they were just like "well yeah", so that wasn't very reassuring. I'm afraid by 6 or 7 months I'll just be laid up! Is anyone else going through this?