@T1Forever I feel for you, but as @Eric2 and @Tim12 mention, I believe it is frozen shoulder as well.
I had it in my left shoulder requiring surgery after months of pt, cortisone shots, and so on.
To not move it is the enemy, but to move it is extraordinarily painful.
I found sleeping in a recliner chair helped, but as you are traveling, that might not be possible. Ice helped me a lot before and after surgery.
Do little activities to help loosen it / keep it from getting worse. There might be some papers online but I recall one where I stood near the wall and walked my fingers up then down; gentle, but movement none-the-less.
I’ll send good thoughts and prayers your way that it eases up so you can enjoy your holiday in Paris.
I recall hearing/reading that there was an autoimmune component to frozen shoulder, so I’m with you on that.
I’m sending out a call for @Terry4 who just came out of a frozen shoulder experience; he might be able to give you some current ideas.