How To Treat Severe Stomach And Chest Pain Inspite Of Taking Zantac?

My daughter is 26 years old and has MR with ADHD and Pervasive Developmental Disorder.She calls me at work crying with severe pain in her stomach at her belly button and then tells me her chest hurts and burns. Sometimes it is difficult to know what she is talking about.We have been to Gastro doc and had scoping and all is fine. She take Dexalant in the morning and Zantac at night for her stomach. What can the pain at her belly button be.