Painful and swollen on left side of upper abdomen. located around stomach area. also experience nausea and loss appetite. other serious diseases ?

Things that usually: cause pain and swelling of the abdomen don't necessarily cause nausea and loss of appetite. Nausea is often caused by stomach inflammation/reflux/ulcer while pain and swelling sounds more mechanical: enlargement of the spleen, constipation.Gall bladder trouble would be expected if pain/swelling in right upper abdomen. This deserves a careful going over by your doctor; make an appointment.Good luck