Frequent stomach pain. What should i do?

I am 24years old, staying in Hostel in pune since 2015. I generally eat very less oily spicy food, but after coming to pune I am dependant on hotel food. I got my first severe stomach pain just before 3months, doctor said after ultrasonograpy that I have acute appendicitis. after that I didn't get any pain in my stomach. But before 7days I did further sonography to check weather I have the same or not. This time doctor said I don't have any appendicitis. But yesterday I got a severe stomach pain. Pain is on right side but not exactly near appendix. Doctor gave me some anti inflammatory and anti acidity medicine. Though I can feel mild pain. I am very much confused of the two different results of usg . What should I do?