Trouble sleeping, stomach hurts and feels like its on fire?

I'm 8 months pregnant, and woke up tonight feeling like my stomach was on fire, plus it feels like I'm about to burst and its painful. The only place on me that's burning up is my stomach. Is this normal? And is it normal after having two c sections, having complete placenta previa and high amniotic fluid, to feel like my stomach is so tight that it hurts?