When you are patent pending, you can possibly sue for damages as your patent application is pending with the USPTO. However, you won't be able to do much until the application is actually granted. Read more

Damages are retroactive back to the filing date provided that the patent application is eventually approved.

If your patent application is denied, all bets are off. For that reason, you won't be able to file a lawsuit or an injunction until the application is actually approved.