I am painting the ceiling in my en-suite, which is the first time I have painted since buying the ex-show house. When rolling, the original paint is lifting and leaving large bare patches to the plaster underneath and the only thing I can think of is to fill the holes

My bedroom paint is peeling off all the way down to the bare drywall and joint compound?? I had this home built in 1996, could it be that room was not primed first? And how can I even it out between the coats of paint and the bare drywall? I’m

I painted latex in a bathroom that I didn’t know had oil based paint on it. Now it is bubbling and I want to fix it. How do I fix the bubbling paint?