It is very common to feel pain in the abdominal and pelvic regions during pregnancy as your uterus is stretching in order to fit the growing fetus. Upper stomach pain may be associated not necessarily with the pregnancy itself, but is a common symptom. Heartburn and gas can cause the stomach region to feel a bit painful, and both are notorious for occurring more often in pregnancy than prior to it.
In pregnancy the main cause of stomach pain is due to contraction of uterus muscles/cramps or gas problems. This is because as the baby’s size increases or when baby moves inside the womb it stretches the uterine muscles and that gives of feeling of hurt to mother.