I'm not sure what you mean when you say the 'share function of your account is off'. Is the sharing button greyed out? If so, you can only share activities that are visible to the Everyone. If you look three icons to the left of the Share button, you will see a lock icon. Click that icon, and select Everyone. Once you've done that, the Share button should be enabled for that activity.
If you want all of your future activities to be visible to Everyone...
Go to the privacy settings for your profile.
Select Everyone for the Who can see your new activities question.
If that isn't the issue you're seeing, please try to describe it as best as you can.
