Access denied hook_menu Drupal 7
Revised:

Your code looks right

3 Things could be the problem


'mypage' could be a banned link.
you don't have access to 'custom_work_mypage_view' form.
Clear your cache.   Without the 'access argument' line you will get access denied.  If you added it then save your file, you will still get access denied until you clear your cache.


My gut feeling is #3.