What Does Acute Pain In The Upper Abdomen Indicate?

hi, i am Soma Paul. Sometime i face acute pain in my upper abdomen due to gas formation. the gas is locked in the left lower intestine and it swells up and become very hard. the pain in upper abdomen is like cramp. i just start vomiting(7-8 times), full sweat, pressure goes down (yesterday i had an attack, pressure was 60/90). my mouth become dry, even i could not able to speak/ go to the bathroom. sometime i feel i much stab a knife in my stomach. that attack generally occurs if i stay without food for 2-3 hrs. so i must have to chew something in every 1-2hrs.