Hard Forceful Cough, Dull Pain Under Lower Ribs. What Could Cause This?
Thanks for posting your question.
The forceful coughing most likely has caused the intercostal muscles present in between your ribs to go in a protective spasm. Since you already have a basic cardiac workup done and an advanced workup lined up, I believe you have nothing to worry. Atleast it would not show up on the right side of the chest. And I assure you that thyroid wont show up in upper right lobe xray either.
As of now you need to keep that cough under control. Any further chest muscle activity will simply aggravate it. Keep chest warm and covered, even give some hot fomentation if possible. Take XXXXXXX breaths as many times as possible.
We are not completely ruling out the possibility of other conditions including cardiac, but we shall find out if its anything other than just costochondritis. For pain you must visit your physician and take Good luck.