Should i be concerned if i have hardness under belly button incision post gallbladder surgery?

When was surgery?: For the first several weeks after surgery there can be some inflammation and "scar tissue" which presents as this. If there is redness increasing pain and/or discharge it may be infected. If it has been years since the surgery you may have a hernia there. Some cancers present as a mass in this area. There are so many things that it could be. You need to see a surgeon for a re-evaluation of this.