Hi Ma am Its a pleasure to answer to your query, as you have mentioned that you have a bicuspid aortic valve and you feel tired at the end of the day. Now let me explain the mechanism happening in your case, aortic valve which is generally tricuspid is bicuspid in your case which means the opening will be less in your case due to which less amount of blood passes through the aorta when your LV pumps due to this less amount of blood is being supplied to your body. Due to this when you are physically active a SUPPLY DEMAND mismatch happens due to which you feel tired and dizzy at the end of the day. It can be take care of with the help of meds upto certain extent but in case if you develop symptoms like giddiness or palpitations then it need to be corrected by means of surgery. Now regarding the stomach pain usually cardiac pain does not refer below diaphragm so the pain which you are feeling is probably non cardiac and for that you need to check with your gastroenterologist. And also get one Serum Uric acid and ASO titre done for your join pain. Good Luck