I Have Been Experiencing Sharp Pain That Comes And Goes

I have been experiencing sharp pain that comes and goes in my back under my rib cage, Like someone is sticking a knife up under my rib cage in the back on the right side and it takes my breath away. Had an xray last week showed nothing. Had a partial removal of the superior lobe on the right side back in 87. This pain hits at any time unexpectedly and only lasts a few seconds and the will subside it might happen three or four time or just once some days it doesn't happen at all.