Thanks for the query
The swelling near the belly button can be most commonly due to paraumblical hernia
which often is an asymptomatic and do not requires any treatment but if it develops symptoms like pain or abdominal bloating
the it do requires surgical repair.
Other than that it can be subcutaneous nodule or cyst in the subcutaneous tissue
which also can be removed through minor surgical procedures.
for better opinion it is recommended to visit a general surgeon
for complete evaluation