hello.i think your lump should be taken seriously and definitely need investigation.
you have not mentioned your age.
diagnosis for the lump in the abdomen has varied causes and it also depends on the age and associated symptoms etc.
one of the common possibility which corelates with your symptoms before and after onset of lump, is tuberculosis
which is completely curable, but that needs thorough evaluation to come to the diagnosis.
there are many other causes depending upon the site.
so please go to a surgeon as early as possible.
all the best.
if you can feel lump very easily its