Pain in the stomach area after recently joining the gym is most commonly due to muscle strain or soreness, known as Delayed Onset Muscle Soreness, which happens when your muscles are not used to new or intense activity; this type of pain is usually mild, felt when stretching or pressing, and improves within a few days. You can manage it with rest, gentle stretching, warm compresses, and staying hydrated, while avoiding heavy workouts until the pain settles. However, if the pain is severe, persistent, associated with swelling, vomiting, fever, or occurs even without movement, it could indicate another issue like a muscle injury or abdominal problem, and you should consult a doctor. Gradually increasing exercise intensity and maintaining proper form can help prevent such discomfort in the future.