20 weeks with twins, getting lower back pain

Abby

I was wondering if I could get some advice. I've been having back pain for a week now and it almost feels like I pulled a muscle especially on my left side. I also have been having sharp pain on the sides of my belly too not to mention some Braxton Hicks which don't hurt just freaky. Does all this sound normal for twin pregnancy? I am seeing the ob in two days