I am experiencing pain waist level on my left side.  It feels like a knife sticking it me just at the bottom of my rib cage.I am 68 and otherwise in good health, no smoking, very little alcohol.  This pain started last night and has been with me all day.  Do I need to see my GP?  Someone suggested gall bladder but I know not where it is located.   .right or left side of the body.  Any advice appreciated.
HI ! Gall bladder is located on the right side of the body and so the pain associated with it will usually be on the right side of upper abdomen. If your pain persists, then I would suggest you to go for a clinical examination by your family physician, who may go for an ultrasound abdomen for you to rule out any other related intro abdominal pathology like inflammation in the pancreas. He may also go for some routine blood test like CBC, and also serum Amylase and Lipase. It could be simply a gastritis, and in that case will subside on intake of some proton pump inhibitor agents. You should also discontinue with your alcohol intake however small amount it might be and avoid fried and spicy food. Wishing you an early recovery.