Intense, stabbing pain, bottom of my rib cage over a 4 hour period, almost feels like really bad heartburn. Went away, now coming back w spasming feel?

See your doctor. Pain at the bottom of your ribs can be from many sources, and certainly, heartburn can be one. However, gallbladder disease and other intestinal problems which often feel like spasms. However, that location can also reflect cardiac pain. Although you're a 30 year old female and that's unlikely, it would be wise to see your doctor in person to explore causes. Especially it's hard to breathe.