so I got my boarding pass for my first flight, but I seem to recall that the last time I flew I got my boarding pass for both flights at the first airport. do I need to go back to the ticket counter?
Yes. Can’t hurt to ask.
I’d either go back to the ticket counter, or go through security and ask the agent at the gate. It seems to me better to be on the safe side in this.
Do you mean the second leg of your flight or the return leg of your flight?
If the second leg then the boarding pass you have is probably good for both; they scan it at the gate and that’s it. If the return leg, you won’t get it until you check in at the airport to return.
That’s assuming that both legs are on the same airline. If they are different, you may have to check in again at your intermediate stop (depending on the airline).
Last time I flew they called me back and apoliged for forgetting to give me both passes, so yes. (Edited to add that the second pass was for a connecting flight.)
I always get both. The only exception is if the continuation is on the same flight, which I assume is not the case. I’d check with a gate agent rather than go back.
ok…it is the same airline, but my pass just lists the one flight so ill go ask someone.
they told me I need to get it at the gate counter in atlanta because I haven’t been assigned a seat yet. 
That suggests that your second plane is over-booked. So get to the gate in Atlanta as early as you can, and find out what the situation is. (Note that, even though it’s been over-booked, you may still have a good chance of getting on that plane, so don’t start panicking yet!)
Depending on the airline and flight, there’s usually a number of seats that are available, but can only be assigned by the gate crew. Sometimes they’re waiting for upgrades to clear, then they’ll give you the seat they originally had for the passenger who moved to first class. Sometimes the flight is temprorarily overbooked, knowing that a certain number of passengers will have taken earlier flights. And there are sometimes certain seats that are empty, but available only after all the other seats are full (certain bulkheads, last row seats, etc.)
Each airline has their own overbooking policies so this may not help.
While getting to the gate as soon as possible is the only thing you can do right now, it has been my experience that the date you initially purchased your ticket may also affect where you stand in the potential bumping line if the flight is indeed overbooked and there really are too many people at the gate who want to fly.
If you have flexibility in your flying, they are overbooked and ask for volunteers, consider it. Don’t accept the first round since airlines usually up the ante if they don’t get enough volunteers.
I’ve often not been assigned a seat, even without an overbooking problem. It seems to happen when I use a low priority travel agent (like for the government) or when I get put into a center seat.
I doubt that he’d not get a boarding pass for the second flight even if there was overbooking, since they can’t know what the situation would be at flight time. Perhaps another connecting flight would be delayed, and there are plenty of seats. Maybe the passes are stuck together?
As for volunteering, it could be lucrative but I’ve read that with the current loads on planes there is a chance that you might have to wait a long time. One might want to get a boarding pass for the substitute flight and not a promise. But when we were coming back from Vegas once my wife volunteered to be bumped, and then managed to volunteer on one of the flights she was put. She showed up at a different airport about an hour later than I did on the original flight, and with a load of vouchers.
Could also just mean you’re making a terminal switch at the connecting airport. That’s what happened last time I flew through Newark. (ugh.)
YMMV - on a couple of occasions I have been checked in for the return leg at the originating airport. This has been for one-day trips on the same carrier, though.