Im sorry don't stress, more then likely its just a strain. The only thing thats concerning is unfortunatley the Aas. Not all aas Is made equal and we can only do so much to know how good the product is that we are putting in our body. Therefor something like hepatitis, gall blader infections, gall stones, and other things that cause pain in the upper abdominal cavity are all very real.
That's why im asking u about blood work and the condition of your heart (heart meaning bp and pulse or ur known vitals. I should have worded that Better though) the reason i asked about Heavey lifting is becuase u said ur stomach was distended and its possible that its some sort of hernia (i was thinking acquired diaphragmatic hernia becuase u said it hurts badley to breath, but the possibility of that would be extermly low) ultimatly ur best bet is to see a doctor, the fact that ur on Aas means that ur pain tolerance is gunna be psychologically higher so that fact that u say its extermly painful means that its def worth getting looked at, and best of luck