Commonly such hypoechoic masses in ovaries are complex cysts
and most resolve after sometime.And in such cases symptomatic treatment can be given.
But if this fails to resolve then,possibility of tumor
needs to ruled out.And in this case you need to get Ca125 and MRI of pelvis done.
A repeat sonography
after few days can help to know whether this has resolved.
Right abdominal pain
can be due to this cyst/hypoechoic mass.
Hope this answers your question.Please ask if there are doubts.