But the underlying problem is your digestion. You need to see someone who can help discover what foods you're having a problem with or if you have some condition such as ciliac disease that is interfering with your ability to digest food. Easiest place to start is to cut out wheat and dairy, the most common culprits, but perhaps you should try seeing a holistic nutritionist. As to the above, I definitely second the digestive enzymes, make sure it's one that has a spectrum of them, not just ones that digest protein, but I'd avoid the simethicone except for occasional use because it will suppress stomach acid, causing your stomach to produce more acid in a rebound effect since it must have an acidic environment to digest protein. DGL and aloe vera juice and peppermint oil enteric oil capsules are examples of substances that can do the same thing without causing that imbalance.
Try taking digestive enzymes just before you eat, and simethicone (Gas-X) if relief is still needed. Both are over-the counter, effective, and harmless.