I'm at 33w and having the same problems. Braxton Hicks, or practice contractions, don't really hurt. They're just uncomfortable. Those feel like a tightening in your stomach and then go away.
With my first pregnancy, and this one, it's been trapped gas or just food disagreeing with me. You can try tums with gas relief or any other kind of gas relief medicine. That might help. Eating more mild foods could also help. Good luck and feel better.