Just as an FYI, in case it helps anyone...

We recently had this same problem. One of our DBs was stuck in a "Recovery Pending" state following a sudden (and unusual) loss of power. (An onsite electrician was to blame.)

Anyhow, it turns out that when the server booted back up, the various drives were a little slower to come online. As a result, when SQL Server went to restore the DB, the drives on which the needed data is stored weren't yet available. (The error logs pointed to which drives were needed).

Once the drives were available, a manual restart of SQL Server fixed the problem and the DB was automatically recovered.

Cheers