Credit Score Drop Help

I’ve been working diligently to raise my credit score and have missed 0 payments, opened 0 accounts, and have been consistently paying off more debt. Both of my credit cards are now paid in full, and I’ve begun paying extra principal on my car loan. I’d finally hit a score of 720, and was excited to see what it would jump to when both my cards registered as paid off. Last night my credit score dropped 27 points and I have no idea why. I recently (a month ago) applied for an apartment, but was approved. 27 still seems like a steep drop for a credit check, and at this point I’m worried about identity theft. How can I learn what cause my score to drop? I’ve been following all of the rules on TurboTax.