There are a few discussion threads here at Marrowforums about spleen issues for MDS patients, including some that mention pain, discomfort, or a feeling of having a full stomach. You are welcome to
search for "spleen" or "splenectomy" and read what others have said.
Upper-left-side abdominal pain can be a sign of a number of conditions, including an enlarged spleen. Since your test results indicate an increased spleen size, that's clearly something for you and your doctor to discuss. The AA&MDSIF mentions spleen removal
here and says it is sometimes necessary when the spleen is larger than 20 to 25 cm, so you could check if your lab results include a comparable measurement. If you end up needing a splenectomy, ask about having it done laproscopically, since that is less invasive than traditional surgery and can require a recovery period of only a couple of days.
The underlying problem, of course, is your MDS. Since you have an IPSS classification of MDS Intermediate 1 and the 5q- abnormality, has your doctor recommended treatment with Revlimid (lenalidomide)?