Q: my phone has a picture of a lock on it in the upper right hand corner

You locked screen rotation. Try changing the physical button above volume controls. You can also access it via Control Center (slide from bottom of phone screen up).

It means your iPhone using portrait screen lock.

Try here >  If the screen doesn't rotate on your iPhone, iPad, or iPod touch - Apple Support

JUDYPIERSOL wrote:

 

My  phone has a picture of a lock  with and arrow around it, on it in the upper right hand corner of the screen to the left of the battery symbol . What does this mean.

Use Control Center on your iPhone, iPad, and iPod touch - Apple Support