my sgs keeps backing out of apps need help

1. settings>accounts and sync>turn off auto-sync
2. check all apps and widgets and turn off auto-sync
3. long press power>turn off data connection
4. long press home>task manager>turn off active applications and clear ram
* Might as well turn off GPS too if you don't need it.

After doing all that, try opening an app. If it runs, it means you have too much stuff going on and there's not enough resources to run anything else. If it still can't run apps, something else is wrong and you're better off doing a factory reset or, last resort, sending the phone back.

Yeah, android loves to multitask so you have to keep those running apps in check or else they'll keep running even when you don't need them.

I constantly clear running tasks with the task manager just to keep things running smoothly.

With android, speed isn't the issue. Task management is.