I would try putting a breakpoint at the beginning of this code behind and F11 through it to see where its bombing out.  One thing I can suggest is move your connection.Close(); to after the catch block since that will leave the connection open. So your code will look more like this:

string newName;
        string newIntro;
        string newEduc;
        string newWork;
         
        newName = h1.Text;
        newIntro = intro.Text;
        newEduc = educ.Text;
        newWork = employ.Text;
 
        string connectionInfo = ConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString;
 
        using (SqlConnection connection = new SqlConnection(connectionInfo))
        {
 
            connection.Open();
            SqlCommand myCommand = new SqlCommand("UPDATE simpleContent SET userName = @newName, infoContent = @newIntro, educContent = @newEduc, workContent = @newWork WHERE userID = @userName", connection);
 
            try
            {
 
                string username = HttpContext.Current.User.Identity.Name;
                myCommand.Parameters.AddWithValue("@userName", username.ToString());
                myCommand.Parameters.AddWithValue("@newName", newName.ToString());
                myCommand.Parameters.AddWithValue("@newIntro", newIntro.ToString());
                myCommand.Parameters.AddWithValue("@newEduc", newEduc.ToString());
                myCommand.Parameters.AddWithValue("@newWork", newWork.ToString());
                myCommand.ExecuteNonQuery();
            }

            catch
            {
                Response.Redirect("http://www.google.co.uk");
            }

             connection.Close();
        }
    }