Welcome to the Boards.
I am not a dr, but it does sound like gerds.
I also suffer from occasional sharp pain under my left breast, that seems to circle right around. I also have sharp pain between my left shoulder blade and spine. Sometimes it is a vague sensation, and other times it can be really painful....Sometimes, I tend to feel it more when I take a deep breath. I am not sure if it is gas, a nerve or what it is....When it acts up, it will be there for a few days, and then slowly decrease.
I also will get the lump in throat feeling from time to time. I have had gerds for about 7 months now. I took otc meds for a few years, until they stopped working. Now I am on protonix, and I am feeling alot better...I still get symptoms, but not as severe.
I am glad that you found the board. It helps to compare symptoms and talk to other people with some of the same feelings and symtpoms.
Take Care, and hope you feel better soon!