The camera on my iphone 4 stopped working about a month ago. Yesterday, Siri voice navigation stopped working. Help.

About a month or so ago the camera on my iphone 4 stopped working. When pushing the camera icon from the home screen, the screen goes black and the goes back to the home screen. Yesterday, while using Siri voice navigation for work out in the field, that function stopped functioning also. Siri will ask " directions to where?" then the initial stages will begin but then shortly go back to home screen with no evidence of the directions to be found. Very frustrating as I use the function for work purposes. Any ideas?