Pain on the left side of the chest and in the lower right side of the abdomen can occur due to different causes such as muscle strain, gas or acidity, or digestive issues. Sometimes chest discomfort may be related to conditions like Gastroesophageal Reflux Disease, while pain in the lower right abdomen could be due to problems such as Appendicitis or intestinal irritation. However, occasional mild pain may also occur from muscle strain or indigestion. If the pain becomes severe or persistent, seek medical attention for proper evaluation.