Swarter
Scott is correct about the tight chokes...Such as the Deadcoyote choke tubes. they are made for shooting out to 45 + yards...Close...10 yards away they shoot like a rifle....
I hae recently changed out one of my shotguns with a modified choke tube because of all the high grass, corn, soybean, and the fox being not yet too spooked...Once the corn and the soybean is cut you can go to the Heavy Full choke guns since your 10 yard shots are going to start to be a bit farther as the season progresses..
Also could be that using 3.5 ammo that the recoil also is knocking you off center too..... This time of the year you can get away with 2 3/4 copper plated # 4 shot or even # 4 buckshot too....Sometime over kill both tight chokes and magnum ammo will hurt you more in the early season.