iphone 7 plus camera stuck

Same issue here.

After reset all settings it worked fine for couple of days and then same issue return.

Reset the settings is not a solution cause it makes you declare everything all over again.

Is it a software bug or hardware problem??

I am currently having the same issue. Try downgrading the iOS, as it appears to be a bug.

Hi

Follow the instructions here, including contacting Apple Support or making a Genius Bar reservation if necessary:

Get help with the camera on your iPhone, iPad, or iPod touch - Apple Support