Braxton hicks

Got a question, i am 22 going on 23 weeks with my di di twins, and ive had braxton hick aince 16 weeks. When get them everythi g gets tight makes it hard to breathe and i get warm, they arent consitant. I also was in the hospital earlier this week for kidney spasm and they loaded me with 7 iv bags of fluids and i drink water through out day so not dehydrated but ive had 4 kids and never had this many through out the day before. Is it because im having twins? Is there any link between alot of Braxton hicks and pre term labor?