The mail is frozen on my i-phone .

After opening up the mail-I went to open a mail and it would not open. The inbox is shaded and it seems to add more emails as they arrive. However, it will not open and the top of the screen shows white space with <inbox on the left and select messages to d..... after that. I have tried to refresh and even turn the i-phone off. It will not do either for me. grannysrs