Frozen brake/stuck

So a couple weeks ago I went and got a car wash in the evening. Came home and parked in the garage with the ebrake up. Next morning went to go to work, put it into gear and let off the ebrake...nothing. It felt like the rear was stuck. So I pumped the ebrake a few times...nothing. Tried reverse...didn't work. I eventually just had to punch it and it finally let go with a loud "pop". I thought I may have broken something, but everything seems fine.

 

Well last week I got another car wash and parked in the garage, but this time didn't use the ebrake (parked in 1st gear). Next morning, same thing happened. I had to "pop" it out again. It felt like the rear right tire.

 

Think this could be icing on the caliper or something? I'm scared I may break something or be stuck forever.

sounds ike a frozen caliper

Sounds like rust on the rotors. It's normal for brakes to be stuck if they're not dried after car wash or left parked outside when it's damp. The pop noise is the rust breaking apart, and is normal even if it sounds like the end of the world.