I just talked to my doctor about this on Tuesday. She says its perfectly normal and not harmful to the pregnancy. Its called round ligament stretching (those deep painful tugs).
I got a belly belt. It looks like a back brace and goes under your belly. I wear it a few hours a day and it really helps. I got mine at motherhood maternity. I think most people don't wear them until later in their pregnancy but my dr suggested it bc I had back surgery in July. I found it really helps the abdominal pain as well.
Re: Stomach stretching
I use a sugar scrub every night in the shower. I also have about 8 pillows hubby hates them but they make me feel so much more comfortable!