My iPhone 4 front camera isn't working?

My front camera is stuck on the shutter screen the back works fine. I restored my phone but it didn't work what else can I do

I've had this problem before with my iPhone 4 as well. I fixed it by tapping the home button twice minusing all the stuff out then turning off my phone for a little bit. Also have a lot of stuff on my phone and am close to capacity, that might play a role in it. Not sure. If it doesn't work after that I'd go to the apple store.