Stomach Ache When Gets Tense, Stressed, Or Eating Food, Taking Injection And Drip For Relief. Cause?

Hello my name is Bernadette and im 33years old,hi doc i just need some advise please,ive got a problem with my stomach when im tense or worked up or feeling stressed,or if im not eating the right food than my stomach gets all worked up with pains like cramp pains that i need to go to hospital for an injection and they put me on drip to release muscle,i just need to know why does it happen all the time when im all worked up and stressed and what is really the course of that,if doc can please tell me what to use for my problem i would gladly appreciate it,thank you doc.