Talk to Gastroenterologist on Abdominal Pain And Motions

hello, urgent!!!!! my sis has been dealing with frequent abdominal pains and loose motion. Initially they said it was ibs for 4 years, then it has moved to symptoms similar to chronic enteritis, she now has frequent loose stools and even those loose stools give her fissure along with abdominal pain, sometimes after passing stool. currently taking homeopathy treatment but no improvement. she also doesnt gain weight she is 24, and weight 38kg // which tests should be done before reaching out to a doctor and what type of doc should she see?