Galaxy S6 :: Phone Locks Within 10 Seconds

Every time I open my phone with my password, it will lock itself within 10 seconds unless I keep "active" on whatever program I'm in. I've had the phone about 3 months. It didn't do this until I called AT&T last week and did some things that were suggested to me to save data. I didn't do anything with the display settings--in fact, I've gone back in to be sure the sleep setting is 10 minutes (unless I otherwise lock it myself).