A hundred arrow a day seems a bit much for only having shot for a few months. Archery is a repetitive motion, and uses the same muscles over and over. Fingertips and shoulders seem particularly prone to overuse.
If you're getting neck pain, it could be from rotating your neck sideways to see the target, when you're facing 90 degrees away from the target. There are things you could do to avoid that, like face the target more squarely, but it is good form to face sideways from the target and rotate your neck toward the target as far as you can rotate it, and I hate to see you change that.
A chiropractor might be able to increase the range of motion of your neck, and that could be an option. Or just shoot less arrows until your body adjusts to this new activity. If it bothers you to shoot fewer arrows, bear in mind that many good archers feel that it does you more good to shoot 20 arrows thoughtfully than to just fling 100 arrows without learning anything from it.