Can I sue in two different jurisdictions (fed court) at the same time

You can sue, because anyone can sue for anything, but it would be a waste of time.  One or the other case (probably the one filed later) will either be dismissed or stayed because of the other pending action, and you might even be sanctioned for wasting everybody's time.  You may still be able to withdraw the Pennsylvania action and commence an action in California, but you can't litigate the same case in two forums at once; don't get two bites of the apple.  The decision of whichever court in which you choose to sue will decide the issues, and can't be overturned by a court in a different state.