sleep/wake button recessed

...i have had this iphone5 for about 2 years, and it has operated perfectly until now ...suddenly and without being dropped or abused, the sleep/wake button is stuck in a recessed position (it is stuck in a position that is not fully out or fully in) ...i can still press it and it responds appropriately

...i would like to know if there is a way to reset it the original position (fully out)?

...i keep the phone in a very good protective case and cannot reach this button in the current position (which means i have to take it out of the case to access this button) ...i am hopeful there is a simple, user friendly solution to this issue ...thank you for any help you can offer