Hello Welcome to health care magic Dear patient, a pulsatile lump in the abdomen near belly button can be either due to a swelling arising from aorta like aortic aneurysm or it can be due to a swelling arising from other structures lying in front of aorta like pancreatic pseudocyst, mesentric cyst, or any lump from stomach , descending colon or intestine or any other structure which ies nfront of aorta can give rise to such pulsatile swellings. Such swellings are not generally due to the side effect of any drug, however the people who take drugs are generally very lean and thin to the extent that their aortic pulsations can normally be seen and felt in their abdomen but there is no lump as such in their abdomen , so if you feel that trere is a lump in your abdomen which pulsates then you should consult a doctor who will get your tests like USG abdomen done to find out the origin of the lump and will advise you accordingly Thanks Dr Arshad