Q: my i phone will connect to my wifi server but when i turn the wifi off it will not connect to me celluar network so i cant send messages or use my phone poroperly at all. how do i fix it?

my i phone wont connect to my cellular network but will connect to my wifi. it recently crashed so i restored it via itunes it restored fine and then wouldnt let me use my internet or send messages because i have no 3G how can i fix this?