Doors and Windows - Door stuck

All of a sudden, 2 doors in my house have become difficult to open. The upper corner is jammed/stuck to the door frame. One door is inside the house leading to the closet, the other one is outside leading to the deck. They're in opposite sides of the house, one is in the northwest corner and the other in the southeast corner of the house. Any suggestions on what to check for, and what to do? Should I be concerned with any structural damage to the house itself? I'm concerned that some structure (column, beam) may be shifting or has shifted in the house. Thanks in advance for all replies.

MP99: I wish I could help with your root cause analysis of the sag in the structure (if that is what it is) but I can only recommend you use heavy weight tooth picks to shim the door hinges to allow for better opening and closing. Good luck. peace: e3 - spamman

Before I'd blame the structure, I'd assume it's caused by humidity. Wood doors expand, causing the binding you describe. Wait a few weeks for things to dry out and see if it improves. Longer term, you could plane the doors to get the right fit.