hi, thanks for sharing a brief history. having pain in the left side upper abdomen can not be appendix for sure and suspecting it as appendix?? pain in the upper left abdomen can be a blunt abdominal injury or a spleen issue. well since you were on a medication the stool you are passing has such odour. I think that should be the case which made you feel the blood in the stool. gastritis is also one of the cause for the left upper chondrium pain. Now what I feel is you may have a catch of the muscle in the left upper hypochondrium. Since you have mentioned that the reports came out clear. screening with the diagnostic ultrasound may reveal any systemic issue if related to any organ can be identified. even if this turns normal than it will be a muscle catch. You can try doing some diaphragmatic breathing exercises and abdominal breathing exercises by placing the hand over the area to strengthen the muscle. Also you can do some straight leg raise by placing hand over the painful area. Also you need to stay in constant touch with you gastroenterologist as to figure out if something related to gastritis is there. because when all reports are normal than a sudden pain can not be possible of the systemic illness. it can be muscular as well. have a discussion with a gastroenterologist and I am sure a proper diagnosis can come closer with diagnostic ultrasound imaging technique. with the grace of God I wish you a speedy recovery.