Does a baby chick breathe inside the egg? How?

The albumen, the protective fluid around the yolk, allows for gas exchange to occur with the outside world via thousands of tiny pores in the shell. I guess you could call that breathing, but not really in the sense we think of breathing.

Diffusion of oxygen through the capillaries that extend through the yolk and albumen - which comes into contact with the airsac at the wider end of the egg. The shell isn't 100% solid.. it's extremely porous and allows for gas exchange (and unfortunately also bacterial/viral exchange which is why you shouldn't handle fertile eggs with dirty hands).

My assumption is yes. I mean, it's like the baby in a women's uterus. They are alive and breathing, too. So I would assume it is the same situation with a chick in an egg. I don't know how though, sorry.

it had to get oxygen from somewhere...

When you breath you inspire air with lugs where oxygen is taken with RBCs and CO2 exhaled out. The chicken inside the egg need oxygen. This oxygen is derived from mother blood through the placenta and not by using his lungs. He uses his lungs only when he come out of his shell.

probaby cuz their alive when they come out so obviously...but idk how though