Moderate to severe pain under the right side of the rib cage mine is the right side, but not under the rib cage... it's higher than that
Pain will often but not always follow a meal with fats or grease nope, had clam chowder for dinner
I've had my gallbladder taken out 4 years and it was indeed excruciating. Yes, I did want to curl up and die whenever I get those nasty spells. You can't sleep, you want it to go away but it just goes on and on. No amount of pain releif will do. The pain can go around from the tummy to the back but for me, hardly on the ribs.
The two symptoms you've written above throw me a bit, particularly with the one after a meal as I will almost always get pains if I get a big hearty meal (bog steaks or BBQ spare ribs). It's 100% guaranteed. I am a skinny little thing so my poor little body probably couldn't take all that meat. The surgery is a simple key hole outpatient surgery.
Good luck and hope you get a diagnosis.