Hi,Dear Thanks for the query to HCM virtual Clinic.
I studied your query with available details given in your query.
I understood your health concerns.
Cause for the lump/painless-
For the right treatment right diagnosis of the cause of the lump in the middle of your
rib cage.
Cause of lump -With the facts given from you,following possibility could be causing such a lump in your case-Epigastric Hernia/Ventral Hernia(if operation history is there with you)/Spigelian Hernia(if lump is away from the center of the upper stomach)
This lump occurs due to weakness in the Central line above the belly button.
As your story of increasing bulge on stomach while getting up or while sitting up confirms this cause.So also the the sever pain goes away,when you push that lump back in to your stomach/abdomen.
Tests to Diagnose it-
USG of the part and
Second Opinion from ER Surgeon is advised Urgently,as it causes sever pain with screaming, which could complicate in to strangulation or obstruction of the hernial contents.
This would help you to plan treatment with your doctor, whom you should plan your visit urgently , before it complicates any more.
Don't Self-treat or medicate in your case as the case may go in to further complications.
Hope this reply would resolve your query and would help you to plan treatment with your doctor.
Hope this would relieve of your health concerns.
Welcome for any further query in this regard before final suggestions are given in your query.
Wishing you fast recovery..
Have a good day.
Dr.Savaskar M.N.
Senior Surgical Specialist.