What Causes Pain In The Upper Abdomen And Dizziness?

Hello I have abdominal pain in my upper side just in the center just before the chest bone., i feel like somebody punched me. , its worse when i lay down sideways ., i also have back pain in my upper center ., i took a glass of water and thats when the pain in my stomach started i started feeling full and then gradually the pounching sensation., it makes it hard to breath as deep breathe make it more uncomfortable and i get dizziness..