Suggest Treatment For Pain Below Sternum

My husband has been experiencing Pain below the sternum, Nausea and throwing up profusely. It is becoming more frequent. It reoccurs about every six weeks or so. He takes the following meds: Fenofibrate, Pantoprazole, naproxen, and lisinopril. One of those is for the acid reflux which he has been taking for years. He has tried to get off it but symptoms get worse when he does.