It could be many things. It could be from slouching or sitting in a way that is causing the diaphragm to be compressed. Do not try to over straighten, just think of relaxing the muscles and allowing yourself to fall into a natural position. It could be injury from working out and doing crunches or other movements. It could be a stomach ulcer.
Another option is to blanch green beans quickly. Blanch your green beans by boiling them for 3 or 4 minutes. This removes the skin of your green beans. You want your beans to be somewhat tender, yet have a little bit of crispness to them. Determine the crispness, by how long you boil them.
1 Cook the green beans in a pot with salted water until JUST tender (about 5 minutes, you can steam the also) drain and transfer to a large bowl of ice water to cool; drain and pat dry with a paper towel (this can be done a day ahead). 2  Melt butter in a skillet over medium heat.