Hi John Cloud,
Have you had a chance to try the taskbar reset suggested above and did the Store icon return after restarting?
Could you also confirm whether this is your personal PC or one managed by a workplace or school and whether any other icons return after you unpin them?
As another test, try creating a temporary local user account:
- Open Settings > Accounts > Other users.
- Under Add other user, select Add account.
- Select "I don’t have this person’s sign-in information", then "Add a user without a Microsoft account".
- Sign out, sign in to the new account, unpin the Store icon and restart the PC.
If the Store stays unpinned there, the issue may be limited to your original profile. Please let me know what happens after the restart, I’ll be happy to help with the next step.