Urg am at 20 weeks 2 days and having major back pain when I lay down. But I know that common because…

Urg am at 20 weeks 2 days and having major back pain when I lay down. But I know that common because I had it with my first one. The only thing I am having trouble pain is across my tummy and it feels like cramps. But every time I go to er they tell me that my tummy is stretching but it was more a normal stretching pain because if feels like Braxton hicks on top of. But I get every other weeks on the pain and the cramps and only time I relize that I get them when I do to much work or running around with my 15 month old son and for some reason I am afraid I might go in labor early any advice on it. My sister only helps when she not at work or my husband will help if he ain't busy do job searching or doing laundry for me.