A bit of good news: From your description, it sounds like your crack is not due to the foundation settling. If you had noticed larger cracks and such accompanying signs as sticking doors and windows, ...

Q: Our bathroom remodel was finished last spring. Within a few months, cracks developed between the shower pan and the wall tiles. The separation is at the drain end of the shower pan only (so far).

So your bathroom needs a new seal and you want to make sure the next caulk you put in does not get those terrible cracks ...

Question: Our pool and deck are 15 years old. The pool needs to be refinished, and the deck has a number of hairline cracks. Five years ago, we had an acrylic texture and paint put over the Kool Deck.