Stomach Pains

Hi, I know from previous tests that I have a hiatal hernia and obviously acid reflux. Lately the pain has been getting worse. I cut back greasy/fatty foods and all dairy since I know I am lactose intolerant. I splurged today since family was in town and had a little bit of both. The pain is immense and makes me want to go to the ER every time. It starts with severe stomach pains in the area where my hernia it. Then it gives me the worst headache. Like my brain is splitting. I have noticed that recently my bowel movements have been odd. Not nearly as much, and back and forth between constipation and diarrhea. I have also been very gassy and belching a lot. If I have a bowel movement or have gas and hold it in I feel immense pain in my pelvic region. I recently had a CT of my abdominal and pelvic region that came back clean, only showing the hernia. However when lying down and my doctor presses on my lower stomach I feel sharp pains. So my doctor referred me to a Gastroenterology specialist who I will see in a few days. He did say gas can cause a lot of pain. A week or two ago it was so bad I did go to the ER, and the doctor gave me a trial of Prilosec, and while taking that and eating clean I felt much better. However the pain can be crippling. Can a hernia/acid reflux really cause this much pain? I know my father suffers from IBS, is that a possibility as well? I am extremely anxious about this visit.