Bump in bellybutton that has slowly increased size over 3 weeks. umbilical hernia? slightly painful when bending down. slight abdominal pains too.

Could be: Although umbilical hernia is a possibility it should not be painful. If indeed painful a more prompt referral to an emergency room is warranted to ensure this is not a life threatening condition.

Could be a hernia: That is the most likely explanation. If you have liver disease it may be related to that. I would suggest seeing your doctor to be fully evaluated, and if needed a referral to a surgeon can be placed. If it suddenly becomes much more painful, red, or you have fevers/nausea/vomiting then go to the ER immediately. Good luck.