I wouldn't recommend using a heating pad. You baby can not ragulat it's temperature and of you over heat the fetus it could cause complications. I have asked my doctor the same thing. I an just 8 weeks and I have alot of pain cuz I have endometriosis. My doctor told me that a warm bath about the same as ur body temperature is ok. Or a hot shawer but not for to long. But definitely not a heating pad. I was also told not to use my heated blanket while I was pregnant because it's the same as a heating pad. Best of luck.
Not on your stomach... Your baby can't regulate temperature and getting the little one too warm can cause damage.
On your tummy, I personally would not do that. Might want to speak to your doctor about the cramps though. Hope you feel better soon!
I don't think it would be good to put it on your tummy. I've used one for my back but has been told to be careful.