Pain MOSTLY when swallowing cold liquids under ribs on left side

[Zenboy10]

I have been dealing with GERD for about 20 years or so - all the usual issues - gas, fullness, sore throat in mornings, sometimes feeling fullness in my throat.
However, the last several weeks I've had a concerning symptom that has me thinking the worst - whenever I drink cold liquids, I can feel the liquid traveling down until it hits a spot on my left side and a sometimes dull, sometimes sharp pain will start up. It goes away quickly after I drink and only seems to be bad when I drink - food, even crunchy, thick food seems to (mostly) be fine.
Any ideas? It's kind of freaking me out now - my doc did blood tests (all fine), put me on a second med and seems to think it's all GERD related...