LUQ "gas pain"
The abdominal luq, for the sake of your question, contains stomach, spleen, pancreatic tail, & colonic
If "gas" is the issue, then consider hollow organs listed above. Many people swallow air into the stomach when laughing, so burping it back up would be natural. Air trapped in the stomach & splenic flexure will be expelled with laughing since the act contracts abdominal muscle.