Your problem seems mostly like Peptic Ulcer
which is also called commonly the stomach ulcer
Maybe it started showing first when you were pregnant, and pregnant women tend to develop upset stomach because of two reasons:
1) a big uterus pushing the stomach up and
2) the stomach muscles not pushing food down because pregnancy
hormones relaxing them.
You could also be having stones in your gall bladder
or injury to pancreas called pancreatitis
. But the most common condition is Stomach Ulcer" for which you need it be treated properly. So please don't delay your doctor appointment because " it doesn't go by itself" and it can get worse.