Reoccurring Stomachaches?

Stomachaches used to be something I only got every now and then, but these days it feels like I get them at least twice a week. It’s often painful stomach cramps, gas, and then diarrhea or a painful bowel movement. I have to be super careful about what I eat because anything can make my stomach upset and cause me to make multiple visits in the bathroom. Could it be something serious or is my stomach just becoming really sensitive?