20 year old home with ceiling cracks getting worse
While I do agree with all of the comments above. Yes, it must be addressed immediately. And yes, the foundation may very well be perfectly fine.

However, obvious increasing size and door operation changes are absolutely not normal settling.

It could be from bad framing --- Structure that was meant to sit on a stud or beam wasn't and was only held by nails.

Water Leak --- Roof or plumbing leak could have rotted wood or metal of a joist hanger.

Excessive load --- May be from remodeling that removed structure or didn't consider structure concerning the load above.

Poor support --- Maybe a shim wasn't installed under mis-measured and/or cut framing or a support post wasn't simply tightened up to what it was to support.

Other trades --- Plumber, Electrician or HVAC may have comprimised the structure in completion of their task. Very common and very overlooked.