Well, this could be one of a few possibilities.
This could be gas, seeing that it got better with the gas-x
This could be reflux- which can cause gas and abdominal pain and this does appear to be associated with food
This could be muscle spasm- as it is worse when you take a deep breath
This could be a blood clot in the lungs
- less likely unless you have shortness of breath
This could be heart disease- unlikely because this is associated with breathing and you have no other symptoms.
This is what I would try-
I would take some mylanta or maalox for reflux. You can also take tylenol for pain of muscle spasm. Apply a warm compress to the area
If you do not notice some relief or if this starts getting worse, then I would see a physician today for evaluation to make sure that it is not one of the more concerning processes that I listed.
Take care and I hope you feel better soon
Please click the GREEN ACCEPT BUTTON if this was helpful so that I will receive credit and compensation for my time. Positive feedback is always appreciated as well. Thank you and good luck!