I have had this before..sometimes on and off for months at a time. It could be IBS, it could be anxiety, it could be acid reflux. The acidic stomach pain feels exactly like acid reflux which can cause uncomfortable stomach pains, chest pains and even feelings in your throat.
I don't think its anything sinister..But I do understand how uncomfortable it is. I've known people, especially a younger girl since I was little, who gets awful stomach aches from anxiety.
I personally throw up when I'm anxious. Another annoying thing.
I hope you feel better.